JPS60120712A - Production of graft copolymer - Google Patents

Abstract

PURPOSE:To produce a graft copolymer excellent in mechanical strength, adhesiveness, and applicability, by graft-polymerizing a vinyl monomer with a specified ozonized propylene polymer. CONSTITUTION:Propylene is polymerized in the presence of a coordination polymerization catalyst based on a Ziegler catalyst, and ethylene is polymerized in the same system to produce an ethylene/propylene block copolymer having an ethylene unit content of 4-15wt%, a MW of ethylene block of 20,000-45,000 and an overall MW of 250,000-350,000. The obtained block copolymer is contacted with an ozone-containing gas of an ozone concentration >=15mg/l at normal temperature for 30-60min to produce an ozonized ethylene/propylene block copolymer. A vinyl monomer (e.g., styrene) is graft-polymerized with this copolymer at a temperature >=80 deg.C and a weight ratio of 2/1-1/3 to a degree of grafting of 45-95%.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a graft copolymer, and more specifically, a specific propylene polymer is treated with ozone, and then a vinyl monomer is grafted onto the copolymer. This invention relates to a method for producing a graft copolymer with excellent physical properties.

Generally, propylene-based polymers such as polypropylene have poor adhesiveness, paintability, printability, etc., and various methods for modifying them have been proposed. For example, a method is known in which polypropylene is exposed to radiation, organic peroxide, or ozone and then graft polymerized with vinyl monomer. A polymer can be obtained (Japanese Patent Publication No. 46-4383).

Special Publication No. 47-8619). However, even in this case, there remains the problem that the molecular weight of polypropylene decreases during ozone treatment, and although this improves secondary processability such as adhesion, it leads to a decrease in mechanical strength. There was a point.

The inventors of the present invention have carried out extensive research in order to solve the above-mentioned conventional problems and to develop a material that maintains sufficient mechanical strength and has excellent visibility and paintability.

As a result, as a propylene-based aggregate to be treated with ozone,
The inventors have discovered that the object can be achieved by using a specific ethylene-propylene propylene copolymer, and have completed the present invention.

That is, in the present invention) a propylene-based aggregate is treated with ozone, and then a vinyl monomer is grafted onto the obtained ozonated propylene-based aggregate to produce a graft copolymer. Ethylene unit content 4-15% by weight.

Molecular weight of ethylene block 20,000-45,000
and the overall molecular weight is 250,000 to 350,
The present invention provides a method for producing a graft copolymer, which is characterized by using an ethylene-propylene block copolymer having the following properties.

The propylene polymer used in the method of the present invention is a trap ethylene di/-propylene block copolymer as described above,
Its properties include an ethylene unit content of 4 to 5%, preferably 7 to 12%! TiM%, published ethylene block 120,000-45,000. Preferably 30,00
0 to 40,000, and the molecular weight of the entire copolymer is 250,000 to 350,000. Preferably 270,
000 to 290,000.

If the molecular weight of the copolymer is less than 250,000, physical properties such as mechanical strength will be poor, while if it exceeds 350,000, moldability will be poor. Moreover, if the ethylene unit content in the copolymer is too small, the molecular weight decreases in the ozone treatment step will be large, which is not preferable.

There are various methods for producing this ethylene-propylene block copolymer, but the most common method is coordination using a commonly known Ziegler type catalyst.
It is obtained by combining propylene and then polymerizing ethylene.

There are various methods for treating this ethylene-propylene block copolymer with ozone, and there are no particular limitations. do it. Specifically, the ozone concentration is 15 to 1V or more, preferably 3
This is carried out by bringing about 0 m9/l of ozone-containing gas into contact with the above ethylene-propylene block copolymer. The processing time at this time may be determined as appropriate depending on the temperature, the concentration of ozone-containing gas, etc.
A rough guideline is approximately 0 minutes. Further, the form of the ethylene-propylene block copolymer to be brought into contact with the ozone-containing gas is not particularly limited, but a form with good contact efficiency is preferable, such as solid forms such as powder, granules, etc.
It is also effective to form a solution in an appropriate solvent.

According to the method of the present invention, a vinyl ++ monomer is graft-polymerized onto the thus obtained ozonized ethylene-propylene block and tHti polymer. This grafting reaction can be carried out under various conditions. For example, as for the method of n (combining), lump-like or simplistic combination is preferable, but semi-emulsified combination is also possible. The temperature may be determined depending on various conditions such as the desired grafting rate, but it should normally be 80'C or higher, preferably 100 to 120C. The ratio of block copolymer and vinyl monomer can be selected as appropriate, but in general, the ratio of block copolymer/vinyl monomer
2 Vinyl monomer -/1 to "/3 (iRJN ratio). The grafting rate of the graft copolymer obtained here varies greatly depending on the reaction conditions, but is usually 45 to 95%, preferably 75%. ~95%.The vinyl monomers used in this case include acrylic acid, acrylic ester, methacrylic acid, methacrylic ester, vinyl acetate,
Examples include vinyl chloride, vinylidene chloride, acrylonitrile, styrene, acrylamide, and butadiene.

According to the method of the present invention as described above, there is no reduction in molecular weight due to decomposition of the ethylene-propylene block copolymer during the ozone treatment process, so the resulting graft copolymer has high mechanical strength. be. In addition, since it is simultaneously subjected to maison treatment, the grafting rate due to the grafting of vinyl monomers is high, resulting in a graft copolymer with excellent adhesiveness and paintability.

The diameter of the graft obtained by the method of the invention is
Combination is effective and widely used as a material for home appliances, automobile parts, etc.

Next, the present invention will be explained in more detail with reference to Examples.0 Example 1 (1) Ozonation of ethylene-propylene block copolymer An ethylene-propylene block copolymer having a median ethylene content of 7. oWIM%, molecules of ethylene block Jij24,000. Molecular weight of copolymer: 270,000
50.9 kg of copolymer powder was placed in a tubular reactor with an internal volume of sooml, and 200ml of water was added thereto.
ozonation was carried out by blowing into the reactor at a rate of hr.

Table 1 shows the rate of molecular weight reduction obtained by measuring the molecular weight every hour from the start of the reaction.

(2) Grafting of styrene For 100 parts of the ozonated ethylene-propylene block copolymer obtained in (1) above, 100 parts by weight of styrene, 1000 parts by weight of water, and 0.5 parts by weight of polyvinyl alcohol. A portion of the mixture was placed in a flask and reacted at 100° C. for 4 hours with stirring to obtain a graft copolymer having a styrene unit content of 18%. Table 2 shows the mechanical strength results of these graft copolymers. Further, Table 3 shows the results of the adhesive tape cross-cut peeling test for these graft copolymers and compositions prepared by mixing them with propylene homopolymer.

Example 2 Example 1 (2) was carried out in the same manner as in Example 1 (2) except that the amount of styrene used was 200% by weight and the reaction time was 6 hours.
% of the graft copolymer was obtained. Table 2 shows the mechanical strength results, and Table 3 shows the results of the adhesion/burlap peel test.

Example 3 In the same manner as in Example 1 (2), except that the amount of styrene used was 300% by weight and the reaction time was 8 hours, the styrene unit content was 63
A graft copolymer with a European weight of % was obtained. The mechanical strength results are shown in Table 2.

Comparative Example 1 Molecules! 155,000 propylene homopolymer 100
A flask was charged with 200 parts of styrene, 1000 parts of water, and 0.5 parts by weight of polyvinyl alcohol, and reacted at 100° C. with stirring for 3 hours.
A graft copolymer containing 1i181Ji% of styrene units was obtained. Table 1 shows the rate of molecular weight reduction, and Table 2 shows the mechanical strength results.

Comparative Example 2 The same procedure as in Comparative Example 1 was repeated except that the amount of styrene used was 200 styrene per portion and the reaction time was 5 hours, but the styrene unit was 45 styrene! #,% of the graft copolymer was obtained. The mechanical strength results are shown in Table 2.

Comparative Example 3 A graft copolymer containing [1163% by weight of styrene units] was prepared in the same manner as in Comparative Example 1, except that in Comparative Example I, the amount of styrene used was 300,111 parts, and the reaction time was 7 hours. Obtained. The mechanical strength results are shown in Table 2.

Comparative Example 4 100 parts by weight of styrene per ioo parts by weight of an ethylene-propylene random copolymer having a molecular weight of 155,000,
Water and soil - a - 0 - 0 - 4t = lt = scolding water 1000 R: 1
1 part and polyvinyl alcohol o, 5 [1 part were charged into a flask and reacted at 100°C for 4 hours with stirring,
A graft copolymer having a styrene unit content of 1BIi weight % was obtained. Table 1 shows the rate of molecular weight reduction, and Table 2 shows the mechanical strength results.

Comparative Example 5 Comparative Example 4 was carried out in the same manner as in Comparative Example 4 except that the amount of styrene used was 200 parts by weight and the reaction time was 6 hours. A graft copolymer of 11% was obtained. The mechanical strength results are shown in Table 2.

Comparative Example 6 A graft conjugate containing styrene at 63 ffiit% was prepared in the same manner as in Comparative Example 4, except that the usage of styrene was 300 tons and the reaction time was 8 hours. I got it. The mechanical strength results are shown in Table 2.

Table 1 Table 2 Table 3 *: The polypropylene continuous chamber used in Comparative Examples 1 to 31C was coated with Planet P, P-2 (black) manufactured by Origin Electric Co., Ltd. at 60°C. After baking for a minute,
100 squares are set in 4 locations, and the number of squares that do not peel off with cellophane tape is calculated per 100 squares.

Claims (2)

[Claims] (1) A propylene-based aggregate is treated with ozone, and then a vinyl monomer is added to the resulting ozonated propylene-based aggregate to produce a graft copolymer. Content 4-15%, ethylene block molecule ff120.000-45
,000, and the entire molecule h't is 250,00
A method for producing a graft copolymer, the method comprising using an ethylene-propylene block copolymer having a molecular weight of 0 to 350,000. (2) Vinyl' [one is acrylic acid, acrylic ester, methacrylic acid, methacrylic ester. The method according to claim 1, wherein the material is vinyl acetate, vinyl chloride, vinylidene chloride, acrylonitrile, styrene, acrylamide or butadiene.