JPH04110314A - Preparation of modified polypropylene - Google Patents

Abstract

PURPOSE:To reduce the decrease in mol.wt. and improve graft rate by treating a specific propylene/non-conjugated diene copolymer with an org. peroxide and graft polymerizing an unsatd. monomer having an electron-attractive group onto the peroxide-treated copolymer. CONSTITUTION:Propylene and 0.01-10mol% non-conjugated diene of the formula (wherein R1 to R6 are each H or 1-6C alkyl; and n is 1-20) are randomly copolymerized in the presence of a Ziegler-Natta catalyst to give a propylene/ non-conjugated diene copolymer, which is treated with an org. peroxide at a temp. lower than the m.p. of the copolymer for 1-10min. 0.1-20 pts.wt. unsatd. monomer having an electron-attractive group is graft polymerized onto 100 pts.wt. the peroxide-treated copolymer in the presence of a radical polymn. catalyst comprising an org. peroxide similar to the above peroxide at a temp. higher than the m.p. of the copolymer for 1-20min.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method for producing modified polypropylene suitable as a compatibilizer for various resin phase parabolites, and in particular to The present invention relates to a method for producing modified polypropylene that has a high yield and can suppress gel formation.

[Conventional technology]

Polypropylene has excellent moldability, insulation, chemical resistance, mechanical strength, etc. due to its low cost, so it is used in films, textiles, etc.
(It is widely used for various purposes such as L1 molded products.

However, polypropylene has poor chemical properties such as structure, adhesion, paintability, printability, and hydrophilicity, and in order to improve these properties, various unsaturated compound monomers are used to craft polypropylene. Research on polymerization is being conducted.

To perform craft polymerization of unsaturated compound monomers on polypropylene, polypropylene is treated with radiation such as electron beams or ultraviolet rays or ozone to form radicals, and the unsaturated compound monomers are reacted, or organic An unsaturated compound monomer is reacted in the presence of a Lanz J. legenerator such as a peroxide (for example, JP-A-48-28092, JP-A-48-62887, JP-A-48
-46689).

However, in such conventional methods, the polypropylene main chain is cleaved during the rancal production process, resulting in a decrease in molecular weight and only a low craft ratio. As a result, problems such as odor and coloring of unreacted particles occur, and the desired properties and properties cannot be obtained. Furthermore, since the molecular weight becomes too small, a problem arises in that the strength of the molded product made by blending it is low.

On the other hand, in view of the fact that propylene white has poor reactivity, the present inventors graft-polymerized a monomer having an electron-withdrawing group and an unsaturated bond to a propylene random copolymer containing a non-conjugated diene comonomer as a modified polypropylene. (Japanese Patent Application No. 1-89221, Japanese Patent Application No. 1-89222).

[Invention or problem to be solved]

However, the propylene random copolymer containing the non-conjugated diene comonomer has a low molecular weight reduction due to graft polymerization and a high grafting rate of the monomer having an electron-withdrawing group and an unsaturated bond. During the modification process, the copolymer itself may be crosslinked.
For this reason, it has been found that a large amount of kelp is generated, which makes it unsuitable as a compatibilizing agent for polymer alloys, and causes problems such as deterioration of appearance when used in applications such as films.

Accordingly, an object of the present invention is to provide a method for producing modified polypropylene that has a low molecular weight drop due to graft polymerization, a high graph 1 ratio, and can suppress gel formation.

[Means to solve the problem]

” - As a result of intensive research in consideration of distribution, the present inventors treated a propylene-nonconjugated diene copolymer with an organic peroxide, and then developed a monomer having an electron-withdrawing group and an unsaturated bond. The inventors have discovered that the modified polypropylene obtained by polymerizing graph (graph) has little molecular weight reduction due to polymerization, has a high grafting rate, and suppresses gel formation, and has conceived the present invention.

That is, fa) a non-conjugated diene comonomer represented by the following general formula % (wherein R1 to R are H or an alkyl group having 1 to 6 carbon atoms, and n represents an integer of 1 to 20) The modification of the present invention in which 0.1 to 10 parts by weight of a monomer having (b) an unsaturated bond such as an electron-withdrawing group is graft-polymerized to 100 parts by weight of a propylene-nonconjugated diene copolymer containing The method for producing polypropylene is characterized by treating the propylene-nonconjugated diene copolymer (a) with an organic peroxide before graft polymerizing the monomer (b).

The present invention will be explained in detail below.

The non-conjugated diene comonomer in the propylene-non-conjugated diene copolymer used in the present invention has the following general formula: represents an integer from 1 to 20.) is a random copolymerization of nonconjugated diene comonomers.

Such non-conjugated diene comonomers include: (i) the terminal carbons of the double bonds at both ends have an alkyl group (in the above general formula, at least one of R1, R2, R5, and R6 is an alkyl group having 1 to 6 carbon atoms; (1) in which both terminal carbons of the double bonds at both ends have hydrogen (in the above general formula, R1, R2, R5, and R6 are all H).

Examples of non-conjugated diene comonomers having terminal carbons or alkyl groups at both ends of the double bond mentioned above are 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-
Methyl-1,4-hexadiene, 1,4-heptadiene, 4-ethyl-1,4-hexadiene, 4,5-dimethyl-1,4-hexadiene, 4-methyl-1,4-hebutadiene, 4 -Ethyl-1,4-heptadiene, 5-methyl-1,4-hebutadiene, 5-methyl-1,4-octadiene, 1,5-hebutadiene, 1,5-octadiene, 5-methyl-1,5 -hebutadiene, 6-methyl-1,5-hebutadiene, 1,6-octadiene, 6-
Methyl-1,6-octadiene, 7-methyl-1,6-
One example is octadiene.

Among these, 7-methyl-1,6-octadiene, 1,4-hexadiene and the like are particularly preferred. Two or more of these non-conjugated diene comonomers can also be used in combination.

Examples of non-conjugated diene comonomers having hydrogen at both terminal carbons of double bonds at both ends include 1,4-pentadiene, 2-methyl-1,4-pentadiene, 2.
4-dimethyl-1,4-pentadiene, 1,5-hexadiene, 2-methyl-1,5-hexadiene, 2,5-
Dimethyl-1,5-hexadiene, 1,6-heptadiene, 2-methyl-1,6-hebutadiene, 2,6-dimethyl-1,6-hebutadiene, 1,7-octadiene,
2-Methyl-1,7-octadiene, 2,7-dimethyl-1,7-octadiene, 1,9-decadiene, 2-methyl-1,9-decadiene, 2,9-dimethyl-1,9
-decadiene, 1,13-tetradecadiene, and the like. Two or more of these non-conjugated diene comonomers may be used in combination.

Among the above-mentioned non-conjugated diene comonomers (1) and (2), one (3) is preferred.

To randomly copolymerize propylene and a nonconjugated diene comonomer, a conventional copolymerization method using a Ziegler-Natsuta catalyst may be applied. In this case, it is desirable that the proportion of the non-conjugated diene is 0.01 to 10 mol%. If the content of non-conjugated diene is less than 0.01 mol%, a high grafting rate cannot be obtained in the subsequent grafting reaction. Moreover, if it exceeds 10 mol%, the crystallinity of the copolymer will be significantly reduced. A more preferable content of non-conjugated diene is 0.1 to 5 mol%.

Note that the random copolymer may be copolymerized with 5 mol% or less of other unsaturated monomers such as ethylene and butene-1. The molecular weight of such a copolymer is usually 10,000 to 10,000 to
It would be appropriate to set it at 1 million.

The monomer (b) to be graft-polymerized to the propylene-nonconjugated diene copolymer (a) as described above has an electron-withdrawing group and an unsaturated bond. Examples of the electron-withdrawing group include a nitro group, a carbonyl group, a carboxyl group, and a nitrile group. Moreover, examples of the unsaturated bond include a vinyl bond and an acetylene bond. Such compounds specifically include acrylamide, N,N-dimethylacrylamide, methacrylamide, N,N-diethylmethacrylamide, 2-vinylpyridine, lysidyl acrylate, glycidyl methacrylate, vinyl isocyanate, vinyldiphenylamine. , N-vinylphthalimide, methyl vinyl sulfide, vinyl sulfonic acid, acrylic acid, maleic anhydride, vinyl triethylsilane,
Allyltriethoxysilane vinyl ketone, acrolein, acrylonitrile, ethyl vinyl ether, vinyl oxylate, vinyl acetate, vinyl trifluoroacetate, vinyl benzoate, allyl stearate, vinyl chloride, vinylidene chloride, styrene, alpha-methylstyrene, etc. Ru. Among these, maleic anhydride, acrylonitrile, glycine methacrylate-1, etc. are preferred.

Next, a method for producing modified polypropylene of the present invention will be explained, in which (b) a monomer having an electron-withdrawing group and an unsaturated bond is graft-polymerized onto (a) the propylene-nonconjugated diene copolymer as described above. .

First, a propylene-nonconjugated diene copolymer is treated with an organic peroxide.

1. Examples of organic peroxides include benzoyl peroxide, lauroyl peroxide, di-tert-butyl peroxide, acetyl peroxide, tert-butyl peroxybenzoic acid, m-chloroperbenzoic acid, dicumyl peroxide, and peroxybenzoic acid. acid, peroxyacetic acid, tert-butylperoxybihale-1,2,5-dimethyl-2, tributylberoxy/\gycine, and the like.

Among these are n'l-chloroperbenzoic acid, 2,5
-dimethyl-2,5-ditertiarybutylperoquine/\xin and the like are preferred.

There are various methods for treatment with such an organic peroxide, for example, (a) propylene-
1] to 100 parts by weight of a non-conjugated diene copolymer, and approximately 0.01 to 1 part by weight of an organic peroxide is added.

After that, the melting point of the propylene non-non-conjugated co-claw coalescence is reached.
at a temperature of two, more preferably 150-300'C,
Melting and kneading can be done for about 10 minutes, preferably 3 to 5 minutes.

If the amount of the organic peroxide added is less than 0.01 part by weight,
The gelation suppression effect of the treatment was not at all significant, and 1
Exceeding the heaviest part is not preferable because the propylene-1-non-nonconjugated diene copolymer and the organic peroxide react excessively, which tends to increase the Kel fraction. A more preferable amount of organic peroxide added is 0.1 to 0.5 parts by weight.

On the other hand, regarding the temperature and time of crosstalk, respectively - ``At Kyumi Minato, the gelation suppression effect of the treatment is not sufficient,'' and if it exceeds 1 limit, organic peroxides such as propylene-nonconjugated diene copolymer This is not preferable because it may cause an excessive reaction and, on the contrary, tend to increase the gel fraction.

In addition to the above-mentioned method, treatment with an organic peroxide can be performed by adding 100 parts by weight of propylene-nonconjugated diene copolymer powder to 100 to 10 parts by weight of an organic solvent such as benzene, toluene, or xylene.
It can also be carried out by dispersing the slurry in 00 parts by weight, adding 1 to 10 parts by weight of organic peroxide thereto, and stirring at a temperature of about 10 to 50°C for about 5 hours to 5 days. can.

If the amount of organic peroxide added is less than 1 part by weight, the treatment will not have a sufficient effect of suppressing kelization, and if it exceeds 10 parts by weight, the propylene-nonconjugated diene copolymer and organic peroxide This is undesirable because it causes excessive reaction and tends to cause an increase in the Kel fraction. A more preferable amount of organic peroxide added is 3 to 5 parts by weight. In addition, the amount of the organic solvent is more preferably 200 to 500 parts by weight.

Regarding the temperature and time of stirring, as in the case of two consecutive melt mixings, if the lower limits are below (1) and (2), the effect of gelation inhibition by the treatment is insufficient, and if the upper limit is exceeded, the propylene This is not preferable because the non-conjugated diene copolymer and the organic peroxide react excessively, which tends to increase the Kel fraction. More preferable stirring temperature and time are room temperature (about 25'C) and stirring time of 2 to 3 minutes.
It is day.

Note that the organic peroxide may be added before, after, or simultaneously with dispersing the propylene-nonconjugated diene copolymer in the organic solvent.

Subsequently, (b)
A monomer having an electron-withdrawing group and an unsaturated bond is graft copolymerized.

Graft copolymerization can be carried out by either a solution method or a melt mixing method. In the case of the melt-kneading method, (a) the propylene-nonconjugated diene copolymer after treatment with an organic peroxide, (b) a monomer having an electron-withdrawing group and an unsaturated bond for modification, and optionally The catalyst is put into an extruder, twin-screw kneader, etc., and heated to a temperature higher than the melting point of the propylene-nonconjugated diene copolymer, preferably 180 to 300°C, and kneaded for 1 to 20 minutes while melting. . In the case of a solution method, the above starting material is dissolved in an organic solvent such as xylene,
Stirring is carried out at a temperature of 90 to 200° C. for 0.1 to 100 hours.

In either case, a normal radical polymerization catalyst can be used as the catalyst. As the radical polymerization catalyst, the same organic peroxide as used in the above peroxide treatment can be used.

The amount of catalyst added is 10% of propylene-nonconjugated diene copolymer.
About 2 parts by weight or less, more preferably 0 parts by weight
．． It is 1 to 1 part by weight. In the present invention, a phenolic antioxidant may 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 graft comonomer to 100 parts by weight of the propylene-nonconjugated diene copolymer (a) is 0.
．． The amount is 1 to 20 parts by weight, preferably 1 to 10 parts by weight.

However, within the range of the above blending ratio, the kraft rate of the comonomer (b) in the resulting modified polypropylene is 0 to 100 parts by weight of the propylene-nonconjugated diene copolymer.
．． It is preferable to appropriately control the amount to be 1 to 10 parts by weight.

The modified polypropylene composition (graft copolymer composition) obtained in this way has a small reduction rate in molecular weight,
The grafting rate is sufficiently high, and the generation of gel is significantly suppressed compared to conventional methods.

[For production]

In the method for producing modified polypropylene of the present invention, a propylene-nonconjugated diene copolymer is treated with an organic peroxide before being graft-polymerized with a monomer having an electron-withdrawing group and an unsaturated bond. Therefore, the molecular weight decrease due to graft polymerization is small, the grafting rate is high, and the generation of gel is suppressed.

The reason why the above effect is obtained is not necessarily clear, but when a propylene-nonconjugated diene copolymer is treated with an organic peroxide, the nonconjugated diene moiety is oxidized. This is thought to be due to the fact that sometimes crosslinking occurs at that part.

〔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.

[11 Non-conjugated diene comonomer/7-methyl-1,6-octadiene: MOD [2] Modifying monomer/maleic anhydride: MAH [3] Pretreatment official peroxide/m-chloroperbenzoic acid: m -CPBA・2,5-dimethyl-2,5-ditertiary-butyl peroxyhexine: POX [Perhexin 25B, manufactured by NOF ■] [4] Radical generator・2,5-dimethyl-2,5-ditertiary-butyl Peroxyhexine: POX (Perhexine 25B, manufactured by NOF ■) Examples 1 to 5, Comparative Example 1 Propylene and 7-methyl-1,6-octadiene (M
OD) at 70°C using a Ziegler-Natsuta catalyst (propylene polymerization catalyst containing titanium trichloride as the main component).
A propylene-nonconjugated diene copolymer (PPDM) was obtained by random copolymerization. The comonomer copolymerization amount and melt flow rate of the obtained propylene-nonconjugated diene copolymer were as shown in Table 1.

100 parts by weight of this propylene-nonconjugated diene copolymer, 300 parts by weight of toluene, and m-
3 parts by weight of chloroperbenzoic acid (m-CPBA) were placed in a flask and stirred at room temperature for the time shown in Table 1.
Treatment with organic peroxides was performed. The melt flow rate of the propylene-nonconjugated diene copolymer after treatment is the first
It was as shown in the table.

100 parts by weight of the propylene-nonconjugated diene copolymer thus treated, maleic anhydride (MAH) as a modifying monomer in the amount shown in Table 1, and radical generation in the amount shown in Table 1. (POX) were put into a laboplasto mill and melt-kneaded at the temperature shown in Table 1 and the screw rotation speed of 80 rpm to carry out graft polymerization.

The melt flow rate, maleic anhydride grafting rate, and gel fraction of the modified polypropylene thus obtained were measured.

The results are also shown in Table 1.

For comparison, polypropylene homopolymer was used instead of propylene-nonconjugated diene copolymer.
Modified polypropylene was produced in the same manner. At that time, the melt flow rate of the propylene-nonconjugated diene copolymer after treatment with a peroxide in the same manner as in Example 1, the melt flow rate of the obtained modified polypropylene, and the grafting of maleic anhydride. rate, and gel fraction in! I decided.

The results are also shown in Table 1.

Comparative Examples 2 to 4 Propylene and 7-methyl-1,6-octacyene (l
vlOD) using a Ziekler-Natsuta catalyst (propyl non-polymerization catalyst containing titanium trichloride as the main component),
By random copolymerization at 70℃, propylene-
A non-conjugated diene copolymer (P P D 1.0 was obtained. The comonomer copolymerization amount and melt flow 1 note of the obtained propylene-non-conjugated diene copolymer were as shown in Table 1. .

This propylene-nonconjugated diene copolymer was not treated with an organic peroxide for comparison.

100 parts by weight of this propylene-nonconjugated diene copolymer, maleic anhydride (λ+ A I(), etc.) in the amount shown in Table 1 as a modifying monomer, and a radical generator (POX) in the amount shown in Table 1. and into the laboplasto mill,
Temperature shown in Table 1 and screw rotation speed 80 rpm
The mixture was melt-kneaded and subjected to kraft polymerization.

The melt flow rate and gel fraction of the modified polypropylonone thus obtained were measured.

The results are also shown in Table 1.

(1) MFR: 23 according to JIS K7210
Measured at 0℃ and 2.16kg load.

(2) Gel fraction Modified polypropylene with a thickness of 0.5 mm
After press-molding approximately 4 g of this into boiling xylene for 24 hours, the weight of the insoluble matter was measured and calculated as follows.

(3) The maleic anhydride graft ratio-modified polypropylene composition was pressed to a thickness of about 50 μs, the IR spectrum was measured, and the maleic anhydride C-
0 bond expansion/contraction peak (1780 cm -') and one of the peaks (840 cm -') peculiar to Aitu Tactical PP.
Calculated from the ratio with m-').

As is clear from Table 1, the modified polypropylene produced by the production method of the present invention has a higher grafting rate of maleic anhydride and a lower molecular weight than the modified polypropylene of Comparative Example 1, in which a polypropylene homopolymer was treated with an organic peroxide. The decrease is small, and the gel fraction is significantly decreased.

Furthermore, the modified polypropylenes of Comparative Examples 2 to 4 in which the propylene-nonconjugated diene copolymer was not subjected to organic peroxide treatment had a high gel fraction.

In this example, the melt flow rates of the modified polypropylenes of Comparative Examples 2 to 4 are smaller than the melt flow rates of the modified polypropylenes of Examples 1 to 5. However, this is considered to be due to the low Kel fraction of the modified polypropylene produced by the method of the present invention, and not due to a decrease in molecular weight.

Examples 6 to 14, Comparative Example 5 Propylene and 7-methyl-1,6-octadiene (M
OD) at 70°C using a Ziegler-Natsuta catalyst (propylene polymerization catalyst containing titanium trichloride as the main component).
A propylene-nonconjugated diene copolymer (PPDM) was obtained by random copolymerization. The comonomer copolymerization amount and melt flow rate of the obtained propylene-nonconjugated diene copolymer were as shown in Table 2.

100 parts by weight of this propylene-nonconjugated diene copolymer and 2.5-dimethyl-2.5-
Ditertiary-butylperoxyhexine (POX) 0
．． 3 parts by weight were put into Labo Plastomill, and the temperature and screen were set as shown in Table 2. The mixture was melt-kneaded for 5 minutes at a rotational speed of 80 rpm and treated with an organic peroxide. The melt flow notes of the propylene-nonconjugated diene copolymer after treatment were as shown in Table 2.

100 parts by weight of the propylene 1-non-nonconjugated diene copolymer thus treated, maleic anhydride (MΔH) in the amount shown in Table 2 as a modification polymer, and further in the amount shown in Table 2. A Rancal generator (POX) was put into a Labo Plastomill, and the mixture was melt-kneaded at the temperature shown in Table 2 and at a screw rotation speed of 80 rpm to obtain Graph I polymerization.

The melt flow rate, maltwinic anhydride grafting rate, and Kel fraction of the modified polypropylene thus obtained were measured.

The results are also shown in Table 2.

For comparison, modified polypropylene was similarly produced using polypropylene nonpolymer instead of the propylene-nonconjugated diene copolymer. At that time, propylene 1 after treatment with organic peroxide was carried out in the same manner as in Example 6.
The melt flow 1 no 1 of the non-non-conjugated diene copolymer nordfluorate propylene, the grafting ratio of 71 twin acid anhydride, and the Kel fraction were determined by ittlJ 3
.

The results are also shown in Table 2.

As is clear from Table 2, the modified polypropylenes of Examples 6 to I11 produced by the production method of the present invention are the same as those of Comparative Example 5 in which polypropylene homopolymer was treated with an organic peroxide.
Compared to modified polypropylene, the grafting rate of maleic anhydride is higher, the molecular weight is lower, and the gel fraction is significantly lower. In particular, the Kel fraction after modification is 0 weight 9
It is suppressed to 6.

〔Effect of the invention〕

The method for producing modified boropropylene of the present invention involves treating a propylene-nonconjugated diene copolymer with an organic peroxide, and then craft-polymerizing a monomer having an electron-withdrawing group and an unsaturated bond. ing. For this reason, the molecular weight decrease due to graft polymerization is small, and even though the grafting ratio is high, the generation of gel is significantly suppressed.

Therefore, the concentration of functional groups introduced by the graft monomer is increased, and chemical properties such as adhesion, paintability, printability, and hydrophilicity are significantly improved.

Furthermore, since the molecular weight decreases little due to the modification treatment, no deterioration in moldability occurs.

Such a modified polypropyl-1-non composition of the present invention is suitable as a compatibilizer to be incorporated into resin compositions for automobile parts, home appliance parts, industrial utility parts, packaging fruit materials, and the like.

Claims (5)

[Claims] (1) (a) General formula below ▲ Numerical formulas, chemical formulas, tables, etc. are included ▼ (However, R_1 to R_6 are H or an alkyl group having 1 to 6 carbon atoms, and n represents an integer from 1 to 20.) Modification in which (b) 0.1 to 10 parts by weight of a monomer having an electron-withdrawing group and an unsaturated bond is graft-polymerized to 100 parts by weight of a propylene-non-conjugated diene copolymer containing a non-conjugated diene comonomer represented by In the method for producing polypropylene, before graft polymerizing the monomer (b),
A method for producing modified polypropylene, which comprises treating the propylene-nonconjugated diene copolymer (a) with an organic peroxide. (2) In the method for producing modified polypropylene according to claim 1, in the general formula of the non-conjugated diene comonomer, R
A method for producing modified polypropylene, characterized in that at least one of _1, R_2, R_5, and R_6 is an alkyl group having 1 to 6 carbon atoms. (3) In the method for producing modified polypropylene according to claim 1 or 2, the proportion of the non-conjugated diene comonomer in the (a) propylene-non-conjugated diene copolymer is 0.01 to 10 mol%. A method for producing modified polypropylene, characterized by: (4) In the method for producing modified polypropylene according to any one of claims 1 to 3, 0.01 to 1 part by weight of the organic peroxide is added to 100 parts by weight of the propylene-nonconjugated diene copolymer. A method for producing modified polypropylene, characterized in that the treatment with the organic peroxide is carried out by adding the propylene-nonconjugated diene copolymer and melt-kneading it at a temperature equal to or higher than the melting point of the propylene-nonconjugated diene copolymer. (5) In the method for producing modified polypropylene according to any one of claims 1 to 3, 100 parts by weight of propylene-nonconjugated diene copolymer powder is mixed with 100 to 10 parts by weight of an organic solvent.
Modified polypropylene is treated with an organic peroxide by dispersing the polypropylene in 0.00 parts by weight, adding 1 to 10 parts by weight of an organic peroxide, and stirring at a temperature of 10 to 50°C. manufacturing method.