JPH06184250A - Method for producing modified polypropylene polymer - Google Patents

Abstract

(57) [Summary] [Structure] A specific styryl-terminated PS macromonomer is melt-kneaded and graft-copolymerized with a polypropylene-based polymer in the presence of a radical polymerization initiator to obtain a specific modified polypropylene-based copolymer. [Effect] A specific modified polypropylene polymer is obtained,
An extremely outstanding effect that can improve secondary processing properties such as rigidity, dimensional stability and printability of polypropylene without lowering the impact resistance, heat resistance and molding processability of polypropylene that could not be achieved in the past. The modified polypropylene-based polymer of the present invention is useful for various molding materials such as films and sheets.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a process for producing a novel modified polypropylene polymer. More specifically, by subjecting a polypropylene-based polymer to melt-kneading graft copolymerization of a styrene-based macromonomer having a styryl group at one end of the molecule in the presence of a radical polymerization initiator, impact resistance and heat resistance of polypropylene are particularly high. The present invention relates to a method for producing a modified polypropylene-based polymer in which secondary processability such as rigidity, dimensional stability, printability and paintability of polypropylene is improved without lowering moldability.

[0002]

2. Description of the Related Art Polypropylene polymers are inexpensive, have excellent heat resistance, chemical resistance, electrical insulation and molding processability, and have a low specific gravity.
It is widely used in various molded products such as home electric appliances and industrial materials such as pallets, packaging containers, and films and sheets including daily sundries.

However, polypropylene-based polymers have problems of insufficient rigidity, poor dimensional stability, and non-polarity, resulting in difficulty in secondary processability such as printability and paintability depending on the use. There is.

In order to solve these problems, many attempts have hitherto been made to introduce a styrene-based polymer represented by polystyrene, which is excellent in rigidity, dimensional stability and secondary processability, into a polypropylene-based polymer. Is coming. For example, a method of blending a polypropylene polymer and a styrene polymer by melt-kneading can be mentioned.

However, the polypropylene-based polymer and the styrene-based polymer are incompatible with each other, and the molded product obtained by mechanically melt-kneading both of them is not easily turned over or delaminated. The raised quality is not practical. Therefore, there is a method of using a rubber substance such as a styrene-conjugated diene block copolymer or a hydrogenated product thereof as a so-called compatibilizing agent in order to improve the compatibility of both.
The rigidity of the obtained molded product is significantly reduced, which is also impractical.

On the other hand, an aromatic vinyl compound represented by a styrene monomer is graft-polymerized to a polypropylene-based polymer in the presence of a radical polymerization initiator by a melt-kneading method which has a simple process and is an industrially advantageous method. Attempts to obtain a composition of a polypropylene-based polymer and a styrene-based polymer all at once are disclosed in, for example, U.S. Pat. No. 3,177,270, JP-A-61-198714 in which a small amount of a crosslinking agent is used in combination.
It is disclosed in Japanese Patent Laid-Open No. 4-33906.

However, in order to improve the physical properties and stabilize the quality of the graft copolymer obtained by these methods, those having a uniform molecular weight of the branch component, that is, the graft component, with respect to the polypropylene polymer which is the trunk component. Since styrene monomer is used to obtain the above, it is technically difficult to control.

In the former two of these examples, since the extruder is used for the melt kneading, there seems to be a problem in industrial production such as volatilization of styrene monomer. In order to solve these problems, JP-A-61-285209 discloses a method of melt-kneading graft copolymerization of a polystyrene-based polyperoxide having radical copolymerizability with a polypropylene-based polymer. Proposed.

However, in the method using this polyperoxide, there seems to be a handling problem relating to safety and a decrease in impact resistance of the resulting graft copolymer,
Further, there is a demand from the market for an industrially useful composition of a polypropylene-based polymer and a styrene-based polymer, particularly a graft copolymer in which the styrene-based polymer is micro-dispersed in the polypropylene-based polymer and is effective for improving the physical properties. ing.

[0010]

Therefore, the object of the present invention is to improve the impact resistance of polypropylene-based polymers,
Improves secondary workability such as rigidity, dimensional stability, and printability, which are defects, without lowering heat resistance and moldability.
A styrene-based polymer is micro-dispersed in a polypropylene-based polymer to provide a novel graft copolymer having improved physical properties, that is, a method for producing a modified polypropylene-based polymer.

[0011]

Therefore, the present inventors have
In view of the situation as described above, the number average molecular weight and the molecular weight distribution can be controlled relatively easily, focusing on a styrene-based macromonomer having a carbon double bond at one end of the molecule, the result of earnest research, It was found that a specific styrene-based macromonomer is easily melt-kneaded and graft-copolymerized with a polypropylene-based polymer in the presence of a radical polymerization initiator to obtain a modified polypropylene-based polymer excellent in various properties. Came to complete.

That is, according to the present invention, a polypropylene polymer and a styrenic macromonomer having a styryl group at one end of the molecule (hereinafter, abbreviated as styryl-terminated PS macromonomer) are melted in the presence of a radical polymerization initiator. The present invention relates to a method for producing a modified polypropylene polymer characterized by kneading and graft copolymerization.

The details of the present invention will be described below. [Structure] The polypropylene polymer used in the present invention is
It is a crystalline polypropylene and contains a polypropylene homopolymer and a copolymer with other α-olefin or polar ethylenically unsaturated compound in which the polypropylene content is 75% by weight or more. Specifically, for example, isotactic polypropylene, crystalline polypropylene-ethylene random copolymer, crystalline polypropylene-ethylene block copolymer, crystalline polypropylene-butene-1 random copolymer, maleic anhydride modified polypropylene, etc. Can be mentioned. These polypropylene-based polymers may be appropriately mixed and used, or other polymers may be mixed and used as long as the properties of the polypropylene-based polymer are not impaired. In the present invention, isotactic polypropylene is particularly preferably used because of its excellent heat resistance.

The macromonomer is an oligomer or polymer having a polymerizable functional group, especially a carbon double bond, at the end of the molecule, and is a high molecular weight monomer.
er) is an abbreviation.

The styryl-terminated PS macromonomer used in the present invention refers to a macromonomer consisting of a polymer skeleton containing a styrene monomer unit as its molecular structure and a styryl group having a polymerizability at one end. is there. The number average molecular weight of the styryl-terminated PS macromonomer is 2,000 to 20,000, preferably 3,0.
It is from 00 to 10,000.

When the number average molecular weight of the styryl-terminated PS macromonomer is less than 2,000, it is difficult to complete 100% of this graft copolymerization reaction as a result of melt-kneading graft copolymerization on a polypropylene polymer. Therefore, a low molecular weight component derived from unreacted macromonomer is mixed in the modified polypropylene polymer, and the impact resistance is inevitably lowered. On the other hand, when it exceeds 20,000, the concentration of carbon double bonds in the macromonomer becomes small, and the graft copolymerizability to the polypropylene polymer is poor, and it is difficult to introduce the target amount of the styryl-terminated PS macromonomer. Becomes

The above number average molecular weight is a value determined by gel permeation chromatography (hereinafter abbreviated as GPC). Next, a method for producing the styryl-terminated PS macromonomer used in the present invention will be described.

The styryl-terminated PS macromonomer is
It can be produced by either anion living polymerization termination method (end-cap method) or radical chain transfer method. In the former anionic living polymerization termination method, for example, a living polystyrene anion is synthesized as an intermediate with a sec-butyl Li initiator, and then this living polystyrene anion is directly added in the presence of a solvent for tetrahydrofuran to obtain several times equivalent amount of p-vinyl. By reacting with benzyl chloride (hereinafter referred to as p-VBC), a styrenic macromonomer having a styryl group at one end is obtained [R. Asami, et.al., Macromolecules, 16,628 (198
3)].

In the latter radical chain transfer method, for example, a styrene monomer is first polymerized with a commonly used radical polymerization initiator in the presence of a chain transfer agent containing a carboxyl group, and a carboxyl group is attached to one end of the molecule. By synthesizing a polymer having the carboxyl group and then neutralizing the carboxyl group with an alkali hydroxide or an alkali metal carbonate to give an alkali metal salt of a carboxylic acid, and then reacting the p-VBC with a mild reaction temperature. It can be manufactured (see Japanese Patent Application Laid-Open No. 4-117407, etc.). Since the styryl-terminated PS macromonomer produced by these methods is usually in a solution state, the styryl-terminated solid PS macromonomer is solid-stated by a precipitation purification method using a poor solvent such as methyl alcohol, n-hexane, and n-heptane. A PS macromonomer is obtained.

In the present invention, the styryl-terminated PS macromonomer thus produced is melt-kneaded and graft-copolymerized with a polypropylene polymer in the presence of a radical polymerization initiator to give the modified polypropylene polymer of the present invention. At that time, other radically polymerizable monomers copolymerizable with the styryl-terminated PS macromonomer in a range not departing from the gist of the present invention, that is, 30% by weight or less, are obtained.
You may use together with the said styryl terminal PS macromonomer.

Aromatic vinyl compounds such as styrene, vinyltoluene, α-methylstyrene, chloromethylstyrene, bromostyrene, and vinylcarbazole are listed only as typical examples of these other monomers. A vinyl cyanide compound such as acrylonitrile or methacrylonitrile; various acrylates such as ethyl acrylate, propyl acrylate, n-butyl acrylate, pentyl acrylate; hexyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate Acrylic acid alkyl esters; various methacrylic acid alkyl esters such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate; acrylic acid, methacrylic acid , Various ethylenically unsaturated carboxylic acids such as crotonic acid, monomethyl maleate, monoethyl fumarate, mono-n-butyl itaconic acid; various ethylenically unsaturated dicarboxylic acids such as maleic acid, maleic anhydride, fumaric acid, itaconic acid Acids; various vinyl ethers such as methyl vinyl ether and butyl vinyl ether; various vinyl halides such as vinyl chloride and vinyl bromide; various vinylidene halides such as vinylidene chloride and vinylidene bromide; vinyl acetate and vinyl propionate Various vinyl esters such as; N-phenylmaleimide, N-methylmaleimide, various maleimide compounds such as N-cyclohexylmaleimide; Various glycidyl group-containing vinyl compounds such as glycidyl acrylate and glycidyl methacrylate; Examples include various (meth) acrylamide compounds such as amide, methacrylamide, N-methylol acrylamide, N-methylol methacrylamide, N-butoxymethyl acrylamide and diacetone acrylamide, which may be used alone or in combination of two or more. Of course.

In the present invention, the styryl-terminated PS macromonomer is used in an amount of 1 to 1 in the modified polypropylene polymer.
A range of 50% by weight is preferred. When the amount of the styryl-terminated PS macromonomer used is less than 1% by weight, modification of the polypropylene-based polymer is insufficient, and when it exceeds 50% by weight, it becomes difficult to exhibit the characteristics of the polypropylene-based polymer. .

The radical polymerization initiator used in the present invention is
There is no particular limitation as long as the polypropylene polymer and the styryl-terminated PS macromonomer are decomposed at a temperature during melt-kneading to generate radicals to cause graft copolymerization, and known ones can be used. However, an oil-soluble organic peroxide is preferable from the viewpoint of graft copolymerizability. Further, since the graft copolymerization is carried out at the melt-kneading temperature, the decomposition temperature for obtaining a half-life of 1 minute is 130 to
More preferably, it is 270 ° C.

As typical examples of such radical polymerization initiators only, ketone peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide; n-butyl 4,4-bis (t-butyl) are exemplified. Peroxy ketals such as peroxy) valerate and 2,2-bis (t-butylperoxy) butane; t-butyl hydroperoxide, cumene hydroperoxide, di-i-propylbenzene hydroperoxide, p-menthane Hydroperoxides such as hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide; di-t-butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2, 5-ge (t-
Butylperoxy) hexane, dialkyl peroxides such as 2,5-dimethyl-2,5-di (t-butylperoxy) hexene-3, t-butylperoxyacetate, t-butylperoxyoctoate, t-butyl Peroxyesters such as peroxy 3,5,5-trimethylhexanoate, t-butylperoxylaurate, t-butylperoxybenzoate, di-t-butyldiperoxyisophthalate; 2,5-dimethyl-2, Peroxyesters such as 5-di (benzoylperoxy) hexane, t-butylperoxymaleic acid, and t-butylperoxy i-propylcarbonate.

The amount of the radical polymerization initiator to be used is 0. 1 with respect to 100 parts by weight of the styryl-terminated PS macromonomer.
The amount is 01 to 10 parts by weight, preferably 0.5 to 5 parts by weight. Further, it is not necessary to remove a diluent such as a solvent which may be present at the time of its use, and on the other hand, a diluent may be added conversely at the time of its use.

The feature of the present invention resides in that a styryl-terminated PS macromonomer is melt-kneaded and graft-copolymerized with the above-mentioned polypropylene polymer in the presence of a radical polymerization initiator. In the case of graft copolymerization, which consists of polymerizing a monomer for forming a "branch" in the presence of a polymer for forming a "stem", an ideal graft in which the entire amount of the branching monomer becomes a branch polymer. In addition to the copolymer, it is inevitable that a polymer containing only a branching monomer, that is, a so-called homopolymer is by-produced.
Therefore, the graft copolymer in the present invention is also understood in this sense, and the modified polypropylene polymer obtained by graft copolymerizing the styryl-terminated PS macromonomer with the polypropylene polymer of the present invention is also styryl. It also includes the case where a homopolymer of the terminal PS macromonomer itself is mixed.

Polypropylene polymer and styryl-terminated P
For the melt-kneading graft copolymerization reaction with the S macromonomer, a known kneader can be used without particular limitation. Exemplifying what can be used as a kneading machine in the present invention, extruders such as a single-screw extruder and a twin-screw extruder; a Banbury mixer, a Brabender plastograph, a plastomill, a multi-screw kneader, a double helical ribbon agitator, etc. Is mentioned. Of these, an extruder is preferable from an industrial viewpoint.

The temperature in the above melt-kneading is generally higher than the melting point or softening point of the polypropylene polymer and the styryl-terminated PS macromonomer and lower than the decomposition temperature, and is in the range of 130 to 270 ° C. preferable. The melt-kneading time varies depending on the blending ratio of each component, the melt-kneading temperature, and the like, and is not particularly limited, but 0.5 to 15 minutes is suitable.

A preferred embodiment for producing the modified polypropylene-based polymer of the present invention is that powdery isotactic polypropylene, styryl-terminated PS macromonomer and radical polymerization initiator are blended in a Henschel mixer, and then blended in an extruder. The blend is supplied from a hopper, melt-kneaded at a temperature of 130 to 270 ° C., discharged from a die, and then extruded pellets are obtained by a strand cutter.

Another preferred embodiment is to supply pelletized isotactic polypropylene to the extruder,
It is melted and kneaded at a temperature of 130 to 270 ° C., a styryl-terminated PS macromonomer is supplied from a powder feeder, and a liquid radical polymerization initiator is supplied from a liquid feeder.

The extruded pellets of the polypropylene-based polymer thus obtained are homogeneous, and pigments and the like are added if necessary, and then the method is industrially applied by any method such as injection molding, blow molding and extrusion molding. Various molded articles that are useful can be manufactured.

Further, in the present invention, when producing the above-mentioned modified polypropylene-based polymer and / or producing a molded article using this modified polypropylene-based polymer, water is used within a range not departing from the gist of the present invention. Inorganic flame retardants such as magnesium oxide and aluminum hydroxide; organic flame retardants such as halogen-based and phosphorus-based; inorganic or organic fillers such as talc, glass fiber, carbon fiber, metal powder, and wood powder;
Additives such as antioxidants, ultraviolet absorbers, light stabilizers, lubricants, antistatic agents, dispersants, cross-linking agents, coupling agents, foaming agents; and other polyolefin resins; styrene-
Butadiene block copolymer (SBS), styrene-
Isoprene block copolymer (SIS), hydrogenated SB
Elastomers such as S (SEBS) and hydrogenated SIS (SEPS); engineering such as aromatic polyester, polyphenylene ether (PPE), polyamide (PA), polycarbonate (PC), polyacetal (POM), polyphenylene sulfide (PPS), etc. It does not matter if you add plastics.

[0033]

EXAMPLES Next, the present invention will be explained more specifically by reference examples, examples and comparative examples relating to the production of styryl-terminated PS macromonomers, but the present invention is not limited to these examples. Absent.

In the following, "part" and "%"
Unless otherwise specified, all are based on weight. Reference Example 1 [Production of styryl-terminated PS macromonomer (A)] High-viscosity stirrer (Chemi Stirrer B2 manufactured by Tokyo Rika Kogyo Co., Ltd.)
(00G type), a reflux condenser, a dropping funnel and a thermometer are attached to a nitrogen-substituted stainless steel flask having an internal volume of 5 l, and 350 parts of a purified styrene monomer (hereinafter abbreviated as SM) and a chain transfer agent are used. 6.1 parts of certain β-mercaptopropionic acid (hereinafter, abbreviated as βMPA) was charged, and the content liquid in the system was heated and heated to adjust the temperature to 146 ° C. and refluxed. Next, SM650 part and βMPA2
A mixed solution with 4.4 parts was dropped from the dropping funnel over 6 hours. During this period, the reaction temperature gradually increased, and when it reached 175 ° C., the system was kept at the same temperature thereafter. After the dropping was completed, 6.1 parts of βMPA was further dropped from the dropping funnel over 1 hour, and then aged at the same temperature for 4 hours to complete the reaction. When the polymerization conversion rate of SM was determined by gas chromatography (GLC), it was 98.7%, and the reaction was substantially completed. It was confirmed by NMR that the obtained product was a styrene-based prepolymer having a carboxyl group at one end of the molecule and an acid value of 16.1 mgKOH / g.
The molecular weight determined by GPC is number average molecular weight (Mn) = 3.
520, weight average molecular weight (Mw) = 7080, dispersion ratio M
It was w / Mn = 2.01. Next, 1020 parts of methyl isobutyl ketone was gradually added to the system to give a solid content of about 5
A 0% solution was prepared, and the system was further cooled to room temperature. Then, 25.0 parts of 48% aqueous sodium hydroxide solution was added and stirred for 1 hour to neutralize the carboxyl groups bonded to one end of the prepolymer. When the acid value in the system was measured, it was substantially 0 mgKOH / g. Then, p-VBC (CMS-1 manufactured by Seimi Chemical Co., Ltd.) was added to this solution.
(4, the same applies hereinafter) 48.5 parts, tetrabutylphosphonium bromide 1.5 parts, and hydroquinone monoethyl ether 0.3 parts are added, and while blowing air into the system at a flow rate of 150 ml / min using an air compressor, 85
The temperature was raised to 0 ° C. and the reaction was carried out at the same temperature for 5 hours. When the system was cooled to room temperature and left to stand, white NaCl fine powder was confirmed at the bottom of the flask.

Then, when the content liquid in the flask was poured into a large amount of methyl alcohol while stirring, white solid powder and granules were precipitated. When this precipitate was filtered off and dried, 1040 parts of powder and granules were obtained. When this powder or granule was analyzed by NMR, it was abbreviated as a styrene-based macromonomer having a styryl group at one end of the molecule [styryl-terminated PS macromonomer (A)]. ] Was confirmed. As a result of measurement by GPC, Mn = 371
0, Mw = 8270, Mw / Mn = 2.23, and a chart showing the molecular weight distribution of one peak with no shoulder was obtained.

Furthermore, for the purpose of confirming the polymerizability of the styryl-terminated PS macromonomer (A) thus obtained, 10 parts of this and 10 parts of SM, 50 parts of toluene and 1-azobis-1-cyclohexanecarbonitrile (hereinafter referred to as A
Abbreviated as CHN. ) Charge 0.1 part into a polymerization tube, degas,
After sealing, the tube was left at 90 ° C. for 24 hours. Then, when the polymerization tube was split and the content liquid was taken out, gelation was not observed,
It was also confirmed by GPC measurement that the peak of the styryl-terminated PS macromonomer (A) as the raw material had disappeared.
This also confirmed the polymerizability of the styryl-terminated PS macromonomer (A) and proved that it was a styrene-based macromonomer having a styryl group at one end of the molecule.

Reference Example 2 [Production of styryl-terminated PS macromonomer (B)] Purified S was prepared in the same flask as in Reference Example 1 by the same procedure.
350 parts of M and 3.4 parts of βMPA were charged, and the content liquid in the system was heated and heated to adjust the temperature to 146 ° C. and refluxed. Then, a mixed solution of 650 parts of SM and 14.4 parts of βMPA was dropped from the dropping funnel over 6 hours. During this period, the reaction temperature gradually increased, and when it reached 175 ° C., the system was kept at the same temperature thereafter. After the dropping, βM from the dropping funnel
3.4 parts of PA was added dropwise over 1 hour, and then aged at the same temperature for 4 hours to complete the reaction. SM by GLC
The polymerization conversion rate of was calculated to be 98.5%, and the reaction was substantially completed. It was confirmed from NMR that the obtained product was a styrene-based prepolymer having a carboxyl group at one end of the molecule and an acid value of 9.8 mgKOH / g. GPC molecular weight is Mn = 5780, Mw = 11
It was 850 and Mw / Mn = 2.05. Next, 1010 parts of methyl isobutyl ketone was gradually added to the system to form a solution having a solid content of about 50%, and the system was further cooled to room temperature. Then, 14.8 parts of 48% sodium hydroxide aqueous solution was added and stirred for 1 hour to neutralize the carboxyl groups bonded to one end of the prepolymer. When the acid value in the system was measured, it was substantially 0 mgKOH / g. Then, 28.5 parts of p-VBC, 1.5 parts of tetrabutylphosphonium bromide, and 0.3 part of hydroquinone monoethyl ether were added to this solution, and air was blown into the system at a flow rate of 150 ml / min using an air compressor. While heating to 85 ° C., the temperature was maintained for 5 hours to carry out the reaction. When the system was cooled to room temperature and left to stand, white NaCl fine powder was confirmed at the bottom of the flask.

Then, when the content liquid in the flask was poured into a large amount of methyl alcohol with stirring, white solid powdery particles were precipitated. When this precipitate was filtered off and dried, 1020 parts of powder and granules were obtained. When this powder or granule was analyzed by NMR, it was abbreviated as a styrenic macromonomer having a styryl group at one end of the molecule [styryl-terminated PS macromonomer (B)]. ] Was confirmed. As a result of measurement by GPC, Mn = 597
0, Mw = 14030, Mw / Mn = 2.35,
Further, a chart showing a molecular weight distribution of one peak without a shoulder was obtained.

Further, the polymerizability of the styryl-terminated PS macromonomer (B) thus obtained was confirmed in the same manner as in Reference Example 1. As a result, no gelation was observed in the content liquid, and the raw material was measured by GPC. Since the peak of the styryl-terminated PS macromonomer (B) disappears, the polymerizability of the styryl-terminated PS macromonomer (B) is confirmed, and the styrenic macromolecule having a styryl group at one end of the molecule is confirmed. Proved to be a monomer.

Reference Example 3 [Production of styryl-terminated PS macromonomer (C)] Purified S was added to the same flask as in Reference Example 1 by the same procedure.
350 parts of M and 2.2 parts of βMPA were charged, the content liquid in the system was heated and heated to adjust the temperature to 146 ° C., and refluxed. Then, a mixed solution of 650 parts of SM and 9.0 parts of βMPA was dropped from the dropping funnel over 6 hours. During this period, the reaction temperature gradually increased, and when it reached 175 ° C., the system was kept at the same temperature thereafter. After completion of dropping, βMP from the dropping funnel
2.2 parts of A was added dropwise over 1 hour, followed by aging at the same temperature for 4 hours to complete the reaction. The polymerization conversion rate of SM was determined by GLC to be 97.6%, and the reaction was substantially completed. Although the obtained product had a very high viscosity, it was confirmed by NMR that it was a styrene-based prepolymer having a carboxyl group at one end of the molecule and an acid value of 6.3 mgKOH / g. GPC molecular weight is Mn = 8
It was 900, Mw = 21890, Mw / Mn = 2.46. Then, methylisobutylketone 1000 was added to the system.
Parts were gradually added to form a solution having a solid content of about 50%, and the system was cooled to room temperature. Thereafter, 9.5 parts of a 48% aqueous sodium hydroxide solution was added, and the mixture was stirred for 1 hour to neutralize the carboxyl groups bonded to one end of the prepolymer. When the acid value in the system was measured, it was substantially 0 mgKOH / g
Met. Then, 19.8 parts of p-VBC was added to this solution,
Tetrabutylphosphonium bromide (1.5 parts) and hydroquinone monoethyl ether (0.3 parts) were added, and the temperature was raised to 85 ° C while blowing air into the system at a flow rate of 150 ml / min. 5
The reaction was held for a period of time. When the system was cooled to room temperature and left to stand, white NaCl fine powder was confirmed at the bottom of the flask.

Then, when the content liquid in the flask was poured into a large amount of methyl alcohol while stirring, white solid powdery particles were precipitated. The precipitate was filtered by filtration and dried to obtain 990 parts of powder and granules. When the powder and granules were analyzed by NMR, a styrenic macromonomer having a styryl group at one end of the molecule [styryl-terminated P
It is abbreviated as S macromonomer (C). ] Was confirmed. As a result of measurement by GPC, Mn = 9020,
Mw = 23300 and Mw / Mn = 2.58, and a chart showing a shoulder-less 1-peak molecular weight distribution was obtained.

Furthermore, as a result of confirming the polymerizability of the styryl-terminated PS macromonomer (C) thus obtained in the same manner as in Reference Example 1, no gelation was found in the content liquid, and the raw material was measured by GPC. Since the peak of the styryl-terminated PS macromonomer (C) disappears, the polymerizability of the styryl-terminated PS macromonomer (C) is confirmed, and the styrenic macromolecule having a styryl group at one end of the molecule. Proved to be a monomer.

Examples 1 to 30 30 mm single-screw extruder (manufactured by Tanabe Plastics Machinery Co., L /
D = 22) with a feeder temperature of 170 ° C and a barrel temperature of 1
The temperature was set to 80 ° C, the die temperature was 190 ° C, and the full flight type screw rotation speed was 20 rpm. Powdered isotactic polypropylene (Hipol B200P manufactured by Mitsui Petrochemical Industry Co., Ltd.), a styryl-terminated PS macromonomer of the present invention and a radical polymerization initiator (Perbutyl Z manufactured by NOF Corporation) at a ratio shown in Table 1 at room temperature with a Henschel mixer. For 5 minutes, these blends were fed to an extruder for melt kneading, and strands were discharged from the die of the extruder. Then, these strands were cut by a pelletizer to obtain pellets, and the modified polypropylene polymer of the present invention was obtained.

With respect to the modified polypropylene polymer of the present invention thus obtained, the amount of styrene component, grafting efficiency and melt flow index (hereinafter abbreviated as MFI) were measured and shown in Table 1 as analytical values. It was

Further, the pellets thus obtained were set at a set temperature of 230 using an injection molding machine (IS-50AM manufactured by Toshiba Machine Co., Ltd.).
Test pieces were prepared at ° C and various physical properties were measured.
The results are shown in Table 2.

The analytical values and the physical property values were determined by the following methods. (Analytical value measurement method) (1) Amount of styrene component Pellets (crushed products in some cases) were analyzed by infrared absorption spectrum analysis (hereinafter, abbreviated as IR analysis) by a conventional method, and calibrations prepared in advance The amount of styrenic macromonomer was determined from the line. In addition, in the table, the measured value was described as the amount of styrene component (%).

(2) Grafting efficiency Pellets (in some cases, pulverized products) were dissolved in a predetermined amount of benzene and poured into 60 volumes by volume of acetone with stirring. After standing overnight, decantation was performed, and then a powdery precipitate was filtered off. The unreacted macromonomer not graft-copolymerized with the polypropylene-based polymer (in some cases, homopolymer) dissolves and disperses in acetone, so it is separated from the precipitating graft copolymer and unreacted polypropylene-based polymer. It The powdery precipitate thus separated by filtration was dried under reduced pressure at 50 ° C., and the weight was measured to calculate the grafting efficiency from the following formula.

[0048] As the denominator of the above equation, the amount of styrene component obtained in (1) above was used.

Further, it was confirmed by NMR and IR analysis that the styrene component was introduced into the polypropylene-based polymer in the separated graft copolymer. (3) MFI Pellets (possibly ground) to ASTM D1238
It was measured according to.

(Physical Property Measurement Method) (1) Bending Elastic Modulus As a substitute characteristic of rigidity, it was measured according to ASTM D790.

(2) Molding shrinkage ratio As a substitute characteristic of dimensional stability, a test piece injection-molded into a mold having a length of 105.0 mm, a width of 50.0 mm and a thickness of 2.0 mm by the above-mentioned injection molding machine is 23 ° C. After being left for 48 hours, the dimension (Lmm) in the longitudinal direction was measured and determined from the following formula.

[0052] (3) Printability As a substitute characteristic of secondary processability, it was measured by the following method.

That is, the test piece was heated at 200 ° C. for 5
The surface of the film having a thickness of 150 μm was heated and pressed for 1 minute, and an oxidative polymerization type ink “POP-S indigo” (manufactured by Dainippon Ink and Chemicals, Inc.) was used on the surface of the obtained film with a RI tester (division roll; ) Was developed and allowed to stand at 23 ° C. for 48 hours, and then the printability was evaluated by a peeling test using a commercially available cellophane tape.

<< Evaluation Criteria >> ◎: No ink transfer on the cellophane tape ○: Less than 10% △: Less than 50% × ···· 50 to 100% (4) Impact strength As a substitute characteristic of impact resistance, Izod impact strength (with notch) was measured at 23 ° C in accordance with ASTM D256.

(5) Vicat softening temperature As a substitute characteristic of heat resistance, it was measured under a load of 1 kg in accordance with ASTM D1525.

(6) Delamination As a substitute characteristic of uniformity, the test piece described above was split,
It was visually determined whether or not the fracture surface was peeled into layers. If delamination is observed, the test piece is not uniform and cannot be put to practical use.

(7) Fish Eyes As a substitute characteristic of moldability, whether or not unmelted fish eyes are present in the above-mentioned 150 μm film,
It was judged visually. In the presence of fish eyes,
It cannot be put to practical use.

Example 4 In the mixing ratio shown in Table 1, Hypol B200P, the styryl-terminated PS macromonomer (A) of the present invention and Perbutyl Z were mixed, and the internal volume was 1-liter in advance. (EX-2X-1000 manufactured by Toseki Seimitsu Co., Ltd.)
I put it in. Then, the blended mixture at 200 ° C. in the kneader,
After kneading the rotor at 20 rpm for 2 minutes, the rotation speed of the rotor was increased to 100 rpm, and the mixture was further kneaded for 5 minutes. afterwards,
The product was extracted from the bottom of the container to obtain a white lump. Allow the lumps to cool to room temperature and use a pulverizer to
The pieces were crushed into squares, analyzed and prepared in the same manner as in Example 1, and then subjected to physical property measurement. The results are shown in Table 2.

[0059]

[Table 1]

[0060]

[Table 2] Comparative Example 1 The Frafuco used in Reference Example 1 was charged with Hypol B200P, styryl-terminated PS macromonomer (B) and p-xylene in a proportion shown in Table 3 so that the solution concentration was 10%, and the mixture was heated to 140 ° C. in the system. Was heated with stirring. After stirring at the same temperature for 1 hour and confirming that the inside of the system became a uniform solution, a predetermined amount of 50% p-xylene solution of perbutyl Z was added dropwise over 1 hour, and then at the same temperature for 10 hours.
The reaction was carried out over time. Then, after cooling the system to 100 ° C,
The solution was poured into a large amount of acetone with stirring to obtain a white crumb-like product. This product was crushed into about 1 mm square by a crusher, analyzed and prepared in the same manner as in Example 1, and then subjected to physical property measurement. The results are shown in Table 4.
It was shown to.

Comparative Example 2 In the same manner as in Example 1, except that styrene monomer (SM) was used in place of the styryl-terminated PS macromonomer (A), the obtained pellets were analyzed and the physical properties were measured after the test pieces were prepared. I served. The results are shown in Table 4.

Comparative Example 3 In the same manner as in Example 1, except that polystyrene (Dick Styrene CR-3500, manufactured by Dainippon Ink and Chemicals, Inc.) was used in place of the styryl-terminated PS macromonomer (A), and a radical polymerization initiator was used. Without using, the obtained pellets were analyzed and test pieces were prepared, and then the physical properties were measured. The results are shown in Table 4.

Comparative Example 4 In the same manner as in Example 1, except that the styryl-terminated PS macromonomer (A) and the radical polymerization initiator were not used, the obtained pellets were analyzed and physical properties were measured after making a test piece for comparison. I went to The results are shown in Table 4.

[0064]

[Table 3]

[0065]

[Table 4] From the results of the above-mentioned Examples and Comparative Examples, the following are found.

From Examples 1 to 4 and Comparative Examples 3 and 4,
The modified polypropylene-based polymer of the present invention obtained by melt-kneading and graft-copolymerizing a styryl-terminated PS macromonomer with a polypropylene-based polymer, especially isotactic polypropylene excellent in heat resistance in the presence of a radical polymerization initiator, has a comparative molecular weight. Polystyrene component, which is a proper “branch” component, is graft-copolymerized with high graft efficiency to isotactic polypropylene, which is a “stem” component, and the obtained molded product is uniform, so polypropylene and polystyrene This performance that cannot be achieved by blending with, that is, secondary workability substituted for rigidity, dimensional stability and printability without degrading impact resistance, heat resistance and moldability of isotactic polypropylene. Can be improved.

From Comparative Example 1, even when a styryl-terminated PS macromonomer is used, when the method of graft copolymerization on a polypropylene-based polymer is solution polymerization rather than melt-kneading, the reaction condition is 40 ° C. for about 10 hours. Grafting efficiency is low and it is difficult to improve rigidity.

From Comparative Example 2, when a styrene monomer is used instead of the styryl-terminated PS macromonomer, in the case of the melt kneading method using an extruder, which is industrially advantageous, a large amount of volatilization of the monomer occurs during the process, which is why There is a problem in terms of safety and hygiene and a decrease in the amount of styrene component introduced. Further, although the impact resistance and rigidity of the obtained molded product are improved, a significant decrease in MFI may occur because of reticulation, which causes a problem in molding processability.

[0069]

The modified polypropylene polymer of the present invention has a styryl-terminated PS specific to the polypropylene polymer.
A macromonomer is formed by melt-kneading graft copolymerization in the presence of a radical polymerization initiator, and a styrene monomer (Comparative Example 2) is used instead of the solution polymerization method (Comparative Example 1) and the styryl-terminated PS macromonomer of the present invention. ), And the performance that could not be achieved by a simple blend of polypropylene and polystyrene (Comparative Example 3), that is, polypropylene's impact resistance, heat resistance, and polypropylene's rigidity and dimensional stability without degrading molding processability. It has an extremely excellent effect that secondary processing properties such as printability and printability can be improved. Furthermore, the modified polypropylene polymer of the present invention is useful for various molding materials such as films and sheets, and has high industrial value.

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[Procedure amendment]

[Submission date] January 7, 1993

[Procedure Amendment 1]

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2. Description of the Related Art Polypropylene-based polymers are inexpensive, have excellent heat resistance, chemical resistance, electrical insulation and molding processability, and have a low specific gravity.
It is widely used in various molded products such as home electric appliances and industrial materials such as pallets, packaging containers, and films and sheets including daily sundries.

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In the latter radical chain transfer method, for example, a styrene monomer is first polymerized with a commonly used radical polymerization initiator in the presence of a chain transfer agent containing a carboxyl group, and a carboxyl group is attached to one end of the molecule. By synthesizing a polymer having the carboxyl group and then neutralizing the carboxyl group with an alkali hydroxide or an alkali metal carbonate to give an alkali metal salt of a carboxylic acid, and then reacting the above-mentioned p-VBC at a mild reaction temperature. It can be manufactured (see Japanese Patent Laid-Open No. 4-117407). Since the styryl-terminated PS macromonomer produced by these methods is usually in a solution state, the styryl in solid form is obtained by a precipitation purification method using a poor solvent such as methyl alcohol, n-hexane, and n-heptane. A terminal PS macromonomer is obtained.

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Aromatic vinyl compounds such as styrene, vinyltoluene, α-methylstyrene, chloromethylstyrene, bromostyrene, and vinylcarbazole are listed only as typical examples of these other monomers. A vinyl cyanide compound such as acrylonitrile or methacrylonitrile; various acrylates such as ethyl acrylate, propyl acrylate, n-butyl acrylate, pentyl acrylate; hexyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate Acrylic acid alkyl esters; various methacrylic acid alkyl esters such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate; acrylic acid, methacrylic acid Maleic acid; crotonic acid, monomethyl maleate, monoethyl fumarate, ethylenically unsaturated carboxylic acids such as various of itaconic acid mono n- butyl
Various ethylenically unsaturated dicarboxylic acids such as maleic anhydride, fumaric acid, itaconic acid; methyl vinyl ether,
Various vinyl ethers such as butyl vinyl ether; Various vinyl halides such as vinyl chloride and vinyl bromide; Various vinylidene halides such as vinylidene chloride and vinylidene bromide; Various vinyl esters such as vinyl acetate and vinyl propionate Various maleimide compounds such as N-phenylmaleimide, N-methylmaleimide and N-cyclohexylmaleimide; Various glycidyl group-containing vinyl compounds such as glycidyl acrylate and glycidyl methacrylate; or acrylamide, methacrylamide, N-methylolacrylamide , (N-methylolmethacrylamide), N-butoxymethylacrylamide, diacetoneacrylamide (meth)
Of course, acrylamide compounds and the like may be used alone or in combination of two or more kinds.

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[Table 3]

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From Comparative Example 1, even when the styryl-terminated PS macromonomer is used, when the method of graft copolymerization to the polypropylene polymer is solution polymerization instead of melt kneading, the reaction conditions are 140 ° C. and 10 hours. Grafting efficiency is low and it is difficult to improve rigidity.

Claims (2)

[Claims] 1. A modified polypropylene polymer characterized by melt-kneading graft copolymerization of a polypropylene polymer and a styrene macromonomer having a styryl group at one end of the molecule in the presence of a radical polymerization initiator. Production method. 2. The number average molecular weight of the styrene macromonomer having a styryl group at one end of the molecule is 2,000 to 2.
The method for producing a modified polypropylene-based polymer according to claim 1, wherein the modified polypropylene-based polymer is 0,000.