JPH03290418A - Production of modified polypropylene - Google Patents

Abstract

PURPOSE:To obtain a modified polypropylene having high graft ratio, free from irritant smell and suitable as a compatibilizing agent to be compounded to a resin composition for e.g. automobile part, appliance part and packaging material or as an adhesive to metal by graft-polymerizing a specific amount of a specific glycidyl compound to PP. CONSTITUTION:The objective modified PP can be produced as a graft copolymer by graft-polymerizing 0.01-30 pts.wt. (preferably 0.1-10 pts.wt.) of a glycidyl compound of formula I (R is H or 1-6C alkyl ; Ar is 6-20C aromatic hydrocarbon group having glycidyloxy group; n is 1-4) (preferably the compound of formula II) to 100 pts.wt. of PP.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for producing modified polypropylene suitable as a compatibilizer for various resin composite soles, and in particular, a method for producing modified polypropylene with little molecular weight reduction due to graft polymerization and a high graft ratio. The present invention relates to a method for producing modified polypropylene with high

[Conventional technology]

Polypropylene is low cost and has excellent moldability, insulation, chemical resistance, mechanical strength, etc., so it is widely used in various applications such as films, fibers, and molded products.

However, due to its structure, polypropylene has adhesive properties and
It has poor chemical properties such as paintability, printability, and hydrophilicity, and in order to improve these properties, research is being conducted on graft polymerization of various unsaturated compound monomers.

JP-A-50-52156 discloses a modified polyolefin composition obtained by melt-kneading a radical generator, a porous filler, a polyolefin mainly composed of propylene, and a polar vinyl monomer at a high temperature higher than the decomposition temperature of the radical generator. Discloses a manufacturing method.

JP-A-52-105993 discloses a method for producing a modified polypropylene, which is characterized in that polypropylene, liquid rubber, and maleic anhydride are reacted in a solvent using a radical promoter.

JP-A No. 55-50040 discloses a method for producing a modified polypropylene having a maleic acid content of 1 to 15% by weight, which is obtained by reacting polypropylene, rubber, and maleic anhydride using a radical generator in the absence of a solvent. Disclosed.

Further, JP-A No. 58-67743 discloses a modified polypropylene partially or entirely grafted with unsaturated carboxylic acids, a crosslinking aid, and an organic peroxide whose 1-minute half-life temperature is 10°C or more higher than the melting point of the modified polypropylene. A modified polypropylene consisting of

[Problem to be solved by the invention]

However, in these methods for producing modified polypropylene, a decomposition reaction of the main chain of polypropylene proceeds simultaneously during the graft reaction, so there is a problem that only a modified product with a low molecular weight can be obtained. Regarding maleic anhydride used for modification, the monomer is sublimable and has a pungent odor, so workability during melt reaction is not necessarily good, and furthermore, there is a risk of discoloration such as yellowing in the resulting modified product. It turns out that there is. Furthermore, with the modified polypropylene thus obtained, it is difficult to sufficiently increase the grafting rate of maleic anhydride, etc., so there is a problem that it is not necessarily satisfactory as a compatibilizer.

Therefore, it is possible to use glycidyl methacrylate, which has an epoxy group, in addition to maleic anhydride, as a modifying monomer, but since glycidyl methacrylate is a liquid, it has poor workability during melt reaction, and it also produces an irritating odor. There are problems such as discoloration and poor reaction efficiency.

Therefore, an object of the present invention is to produce a modified polypropylene that is suitable as a compatibilizer for various resin-based acids, has little molecular weight decrease due to graft polymerization, has a high grafting rate, and has good work efficiency during grafting reaction. The purpose is to provide a method.

[Means to solve the problem]

As a result of intensive research in view of the above objective, the present inventors have found that the above objective can be achieved by modifying polypropylene in the presence of radicals using a specific glycidyl compound having an acrylamide group and an epoxy group. They discovered what they could do and came up with the present invention.

That is, the method for producing modified polypropylene of the present invention includes (a) 100 parts by weight of polypropylene, and (b) a block copolymer or random copolymer of the following general formula: and ethylene. For copolymers, the ethylene content is 10
% by weight is marginal. Such polypropylene resin usually has a melt flow rate of 0.5 to 80 g/10 m1n.
(MFR5JISK7210.Load 2.16kg, 2
3C1℃).

Furthermore, modifying monomers that can be used in the method of the present invention include:
The following - boat formula (1): (wherein, R is H or an alkyl group having 1 to 6 carbon atoms,
Ar is an aromatic hydrocarbon group having 6 to 20 carbon atoms and having at least one glycidyloxy group, and n is 1 to 4.
represents an integer of 0.01 to
It is characterized by graft polymerizing 30 parts by weight to form a graft copolymer.

The present invention will be explained in detail below.

(a) Polypropylene that can be used in the method of the present invention is not limited to a homopolymer of propylene, but propylene (in the formula
R is H or an alkyl group having 1 to 6 carbon atoms, and Ar is a C 6 alkyl group having at least one glycidyloxy group.
~20 aromatic hydrocarbon groups, n represents an integer of 1 to 4).

Preferred glycidyl compounds include the following formula (
2) can be mentioned.

(In the formula, R is H or an alkyl group having 1 to 6 carbon atoms,
n represents an integer of 1 to 4> Such glycidyl compounds are disclosed in, for example, JP-A-60-1
It can be produced by the following method shown in No. 30580.

First, an aromatic hydrocarbon having at least one phenolic hydroxyl group and an alkyl ether derivative of N-methylol acrylamide, N-methylol methacrylamide, or N-methylol methacrylamide.
These are hereinafter referred to as N-methylolacrylamides.By condensing these with an acid catalyst, the following general formula (3
) (wherein R is H or an alkyl group having 1 to 6 carbon atoms,
Ar' has at least one hydroxyl group and has 6 carbon atoms
~20 aromatic hydrocarbon groups, and n represents an integer of 1 to 4. ) is produced.

The aromatic hydrocarbon having at least one phenolic hydroxyl group is not particularly limited, but examples include phenol, 0-cresol, m-cresol, p-cresol, 2.6-xylenol, 2.4-xylenol,
- Phenolic compounds such as chlorophenol, m-chlorophenol, 0-phenylphenol, p-chlorophenol, 2゜6-diphenylphenol, polyphenolic compounds such as hydroquinone, catechol, phloroglucinol, 1-naphthol, 2- naphthol, 9
Examples include polycyclic hydroxy compounds such as -hydroxyanthracene, bisphenols such as 2,2-bis(4-hydroxyphenyl)propane (bisphenol-A), and bis(4-hydroxyphenyl)methane.

Next, by glycidylating the hydroxyl group of the compound represented by the above general formula (3), a glycidyl compound represented by the general formula (1) can be obtained.

This glycidylation is preferably carried out by carrying out an addition reaction between the compound represented by the general formula (3) and shrimp halohydrin, followed by dehydrohalogenation with a caustic alkali.

The addition reaction with shrimp halohydrin is carried out using a phase transfer catalyst.

As the shrimp halohydrin, epichlorohydrin, shrimp bromohydrin, shrimp iodohydrin, etc. can be used.

Examples of phase transfer catalysts include quaternary ammonium salts such as tetrabutylammonium bromide, trioctylmethylammonium chloride, and benzyltriethylammonium chloride; quaternary phosphonium salts such as tetraphenylphosphonium chloride and triphenylmethylphosphonium chloride; Quaternary arsonium salts and the like can be used.

The amount of the phase transfer catalyst used is 0.01 to 100 mol%, based on 100 mol% of the compound represented by general formula (3).
It is preferable to use it within the range of . A particularly preferred amount of phase transfer catalyst used is 0.05 to 10 mol%.

In addition, the reaction time and reaction temperature are 50 to 120℃ for 5 minutes to 2
The time is preferably 10 to 30 minutes at 80 to 110°C.

Subsequently, dehydrohalogenation is performed using caustic alkali.

As the caustic alkali, caustic soda, caustic potash, lithium hydroxide, etc. can be used. These can be used as solids or as aqueous solutions. Further, as a catalyst for dehydrohalogenation, the same one as the above-mentioned phase transfer catalyst can be used. Catalysts other than the phase transfer catalysts mentioned above include crown ethers, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, and the like.

The amount of the caustic alkali to be used is preferably equimolar to the compound represented by the general formula (3). More preferably, 1.1 to 1.5 times the mole is used. In addition, the reaction time and reaction temperature were 109 to 3 hours at 20 to 90°C,
More preferably, the temperature is 40 to 70°C for 30 minutes to 2 hours.

Such modification (graft polymerization) of polypropylene with a glycidyl compound can be carried out by either a solution method or a melt mixing method. In the case of the melt mixing method, polypropylene, the above-mentioned glycidyl compound for modification, and a catalyst if necessary are put into an extruder or twin-screw kneader, etc.
0.1 to 20 while melting by heating to a temperature of ~300℃
Knead in minutes. In the case of a solution method, the above starting material is dissolved in an organic solvent such as xylene, and the starting material is dissolved at a temperature of 90 to 200°C.
This is carried out with stirring for 1 to 100 hours. In either case,
Usual radical polymerization catalysts can be used as catalysts, such as benzoyl peroxide, lauroyl peroxide, di-tert-butyl peroxide, acetyl peroxide, tert-butyl peroxybenzoic acid, dicumyl peroxide, peroxybenzoic acid, peroxyacetic acid. , tertiary-butylperoxypivalate, 2,5-dimethyl-2,5-ditertiary-butylperoxyhexine, and other peroxides, and diazo compounds such as azobisinbutylonitrile (IJ) are preferred.

The amount of the catalyst added is about 0.1 to 10 parts by weight per 100 parts by weight of the modified glycidyl compound. In the present invention, a phenolic antioxidant can be added during the graft reaction. However, if a radical polymerization catalyst is not added, it is preferable not to add it.

The blending ratio of the glycidyl compound to 100 parts by weight of the polypropylene (a) is 0.01 to 30 parts by weight,
Preferably it is 0.1 to 10 parts by weight. If the amount of the glycidyl compound is less than 0.01 parts by weight, it is difficult to achieve a high grafting rate, and if it exceeds 30 parts by weight, the molecular weight of the modified polypropylene obtained will decrease.

The modified polypropylene (graft copolymer) obtained in this way has an extremely small reduction rate in molecular weight. This makes it possible to obtain modified polypropylene with a high molecular weight that cannot be obtained by conventional methods. Furthermore, the glycidyl compound used in the method of the present invention does not produce an irritating odor during modification, and does not discolor as occurs when modified with maleic anhydride or the like.

[For production]

In the method for producing modified polypropylene of the present invention, polypropylene is modified in the presence of radicals using a specific glycidyl compound having an acrylamide group and an epoxy group.

For this reason, it is suitable as a compatibilizer for various resin compositions, has a low molecular weight drop due to graft polymerization, has a high grafting rate, does not produce an irritating odor during modification, and can be modified with maleic anhydride, etc. It is a modified polypropylene that does not discolor like the case.

The reason why such an effect is obtained is not necessarily clear, but a specific glycidyl compound is used as a modifying monomer, and this glycidyl compound is
It is a monomer that has an acrylamide group at one end and an epoxy group at the other end, and also has a benzene ring, so it has excellent properties such as reactivity and heat resistance, and is modified with such monomers. This is thought to be due to the

〔Example〕

The present invention will be explained in further detail by the following specific examples.

In addition, in each Example and Comparative Example, the following materials and additives were used.

[1] Polypropylene/HPP: Propylene homopolymer [melt flow rate (MFR230℃2.16kg load H, 5g/
10 minutes, and 9g/10 minutes]・BPP: Propylene-ethylene block copolymer [ethylene content 7.5% by weight
, melt flow rate) 1.0 g/10 minutes]・RPP: Propylene-ethylene random copolymer [ethylene content 3% by weight, melt flow rate 1.0 g/10 minutes] [2] Modifying monomer・AXE: below Glycidyl compound represented by the general formula [
Manufactured by Kanebuchi Chemical Co., Ltd.] ・GMA nigericidyl methacrylate [manufactured by NOF Corporation] ・MAH: Maleic anhydride [3] radical generator ・POX: Perhexin 2-58 [Manufactured by NOF Corporation]
Examples 1 to 7, Comparative Examples 1 to 5 Various polypropylenes (PP) shown in Table 1 and
A modifying comonomer of the type and amount shown in the table, and a first
Tri-blend the amount of radical generator shown in the table using a Henschel mixer, then use Labo Plastomill.
Graft polymerization was carried out by melt-kneading at 200° C. and 80 rpm for 5 minutes.

The melt flow rate, grafting rate of the modifying monomer, and hue of the modified polypropylene thus obtained were measured.

The results are also shown in Table 1.

In addition, 50 parts by weight of this modified polypropylene and polybutylene terephthalate (PBT: manufactured by Kijin ■, TRB-K)
50 parts by weight were melt-kneaded in a lab blast mill at 200° C. for 5 minutes at 80 rpm to carry out graft polymerization.

The graft ratio of polybutylene terephthalate in the obtained polypropylene-polybutylene terephthalate graft copolymer was measured.

The results are also shown in Table 1.

(1) MFR: Value measured according to JIS 721O.

(2) Grafting ratio of the modifying monomer: ■For AXE: After dissolving the modified polypropylene in boiling xylene and removing the insoluble components, the dissolved components are precipitated with menol, and this is pressed to a thickness of approximately 50 mm. , T.R.
The spectrum was measured, and the peak (1648 cm-') of the expansion and contraction of the C=○ bond of AX and the
From the ratio with one of the characteristic peaks (840 cm-'),
Calculated.

■For MAR: Press modified polypropylene to a thickness of about 50 cm, measure the TR spectrum, and find the peak of expansion and contraction of the C=○ bond of maleic anhydride (1480 cm-')
and one of the peaks (8
40 cm-').

■For GMA: Press modified polypropylene to a thickness of approximately 50 mm, measure the TR spectrum, and measure the peak of expansion and contraction of the glycidyl group of glycidyl methacrylate (1150 mm).
It was calculated from the ratio between c+a-') and one of the peaks (840 cm-') characteristic of Aitsu Tactical PP.

(3) Judgment was made visually.

(4) Grafting ratio of polybutylene terephthalate: The modified polypropylene-polybutylene terephthalate graft copolymer was ground to a particle size of 0.246 mm or less, and
The mixture was extracted with metaxol at ℃ to remove unreacted polybutylene terephthalate. After that, from the remaining sample, a film with a thickness of 50 to 100 ta was created by press molding, and the TR spectrum was measured, and the peaks (700, 1504, 1580 cm-' ), the content was calculated using the following formula.

As is clear from Table 1, the modified polypropylene produced by the Kaizo method of the present invention has a small increase in the melt flow rate after modification, can increase the grafting ratio of the modifying monomer, and is free from discoloration such as yellowing. There was no pungent odor. Furthermore, the grafting rate when polybutylene terephthalate was graft copolymerized to this modified polypropylene was also high.

On the other hand, the modified polypropylenes of Comparative Examples 1 to 4 in which maleic anhydride was used as the modifying monomer had a low grafting rate of maleic anhydride, turned pale yellow, and had a pungent odor. Furthermore, when polybutylene terephthalate was graft copolymerized, the grafting rate was low.

Furthermore, the modified polypropylene of Comparative Example 5 in which glycidyl methacrylate was used as a modifying monomer also had a low grafting rate of maleic anhydride and turned pale yellow. Furthermore, when polybutylene terephthalate was graft copolymerized, the grafting rate was low.

The reason why the graft ratio of the modified polypropylene of each comparative example is low when it is used as a graft copolymer is considered to be that the graft ratio of the modifying monomer of the modified polypropylene itself is low.

Further, the value of the melt flow rate is usually correlated with the molecular weight, and it can be inferred that the larger the value, the lower the molecular weight.

〔Effect of the invention〕

In the method of the present invention, polypropylene is modified in the presence of radicals using a specific glycidyl compound having an acrylamide group and an epoxy group.

Therefore, it is suitable as a compatibilizer for various resin compositions, has a low molecular weight decrease due to graft polymerization, has a high grafting rate, and has a high grafting rate when the resulting modified product is graft-polymerized with a different type of polymer. is high;
This modified polypropylene has no irritating odor during the grafting reaction and has good work efficiency.

Therefore, the concentration of functional groups introduced by the graft monomer increases, which greatly contributes to improving chemical properties such as adhesion, paintability, printability, and hydrophilicity. , coloring problems are also greatly reduced.

Further, since the molecular weight decreases little, deterioration of moldability does not occur.

The modified polypropylene of the present invention is suitable as a compatibilizer to be added to resin compositions for automobile parts, home appliance parts, industrial material parts, packaging materials, etc., and as an adhesive for metals.

Claims (1)

[Claims] (a) Based on 100 parts by weight of polypropylene, (b) The following general formula: ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, R is H or an alkyl group having 1 to 6 carbon atoms) and
Ar is an aromatic hydrocarbon group having at least one glycidyloxy group and having 6 to 20 carbon atoms, and n is an integer of 1 to 4.
A method for producing modified polypropylene, which comprises graft polymerizing parts by weight to obtain a graft copolymer.