JPH07173229A - Production of modified polyolefin - Google Patents

Abstract

PURPOSE:To produce, by a melt kneading method, a modified polyolefin which has a high graft ratio and greatly improved compatibilizing function and adhesive properties. CONSTITUTION:A modified polyolefin is produced by grafting 0.1-20 pts.wt. unsatd. carboxylic acid or its deriv. onto 100 pts. wt. polyolefin in the presence of divinylbenzene in an amt. of 0.1-1 pt. wt. based on 1 pt. wt. of the acid or its deriv.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a modified polyolefin having a high graft ratio.

[0002]

2. Description of the Related Art Polyolefin has the characteristics that it is lightweight, has excellent impact resistance, and has good environmental characteristics such as moldability, water resistance, and chemical resistance. Therefore, conventionally, an attempt has been made to form a material having superior characteristics by copolymerizing or blending with a different kind of polymer to form an alloy, combining with various inorganic materials to form a composite material, or laminating on a metal. Has been. However, polyolefin, which is a high molecular weight hydrocarbon, has poor compatibility with different types of polymers having characteristic groups, particularly polyesters, polyamides, polyphenylene sulfide, polyphenylene oxide, and other so-called engineering plastics. However, the impact resistance and mechanical strength are low, and there is a problem that surface peeling occurs in the molded product. Further, the polyolefin alone did not have good adhesiveness to inorganic materials and metals.

Therefore, a compound having a specific structure, for example, an unsaturated dicarboxylic acid anhydride, particularly maleic anhydride (MAH), is grafted onto the polyolefin to improve its physical properties. If the graft ratio of maleic anhydride or the like is increased, the function of the different polymer as a compatibilizing agent and the adhesiveness can be greatly improved, so that technical development thereof has been desired. However, upon grafting, it is necessary to use a peroxide or the like as an initiator or to irradiate with ultraviolet rays or radiation, and as a result, a part of the polyolefin resin causes an oxidation reaction or decomposes. However, only a modified polyolefin having a low molecular weight was obtained, and the graft ratio could not be increased.

Further, JP-A-4-189809 and JP-A-4-1982.
In 06, a solution method of swelling a polyolefin in the presence of a solvent and co-grafting ethylene is disclosed.
Since the apparatus and the manufacturing process such as the reaction and the solvent separation after the reaction are complicated, a method for improving the graft ratio by a simpler method has been demanded. For this reason, a method of performing a grafting reaction by a melt-kneading method has been considered, but it has not been possible to obtain a sufficient graft ratio.

[0005]

An object of the present invention is to provide a method for producing a modified polyolefin in which decomposition of the polyolefin is suppressed and the graft ratio of unsaturated carboxylic acid is increased.

[0006]

Means for Solving the Problems As a result of studies conducted by the present inventors to solve the above-mentioned problems, the presence of divinylbenzene in grafting an unsaturated carboxylic acid onto a polyolefin suppresses decomposition of the polyolefin and causes The inventors have found that the graft ratio of a saturated carboxylic acid can be improved and have reached the present invention.

[0007]

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, (1) in graft polymerization of an unsaturated carboxylic acid or a derivative thereof onto a polyolefin to produce a modified polyolefin, 0.1 part of the unsaturated carboxylic acid or a derivative thereof is added to 100 parts by weight of the polyolefin. To 20 parts by weight and divinylbenzene in an amount of 0.1 to 1 part by weight per 1 part by weight of the unsaturated carboxylic acid or its derivative, a method for producing an unsaturated carboxylic acid-modified polyolefin, (2) modified polyolefin The method for producing a modified polyolefin according to the above (1), wherein the graft polymerization reaction is carried out using an extruder in the production of the above, (3) the method for producing a modified polyolefin according to the above (1), wherein the polyolefin is a polypropylene resin, And (4) the unsaturated carboxylic acid or its derivative is maleic. Or to provide a method for producing a modified polyolefin (1) is a derivative thereof.

As the polyolefin used in the present invention, ethylene, propylene, butene-1, hexene-
1,3-methylbutene-1,4-methylpentene-1,
Examples thereof include homopolymers of α-olefins such as heptene-1, octene-1, and decene-1, copolymers of two or more of these, or a mixture thereof. Of these polyolefins, polyethylene and polypropylene are preferred. In the present invention, polypropylene includes a homopolymer of propylene, a copolymer of propylene and ethylene or an α-olefin other than propylene, a copolymer such as a block and a graft, and a mixture thereof. A propylene-ethylene random copolymer is preferred.

As polyethylene, the melt index (MI, JIS K7210, load 2.16 kg, 190 ° C.) 0.01-1
00g / 10 minutes, density (ASTM D1505) 0.90-0.98g / c
m ³ is preferable. Polyethylene also includes those obtained by copolymerizing α-olefin having a prime number of about 4 to 20 up to about 20 mol%. Examples of such polyethylene include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE), and super high density polyethylene.

In the present invention, the polyolefin also contains an olefin elastomer. Here, the olefin elastomer means α such as ethylene, propylene, butene-1, hexene-1, and 4-methylpentene-1.
-It means a copolymer rubber of two or more kinds of olefins, or a copolymer rubber of an α-olefin and another kind of monomer. Specific examples of the copolymer rubber of two or more kinds of α-olefins include ethylene-propylene copolymer rubber (EPR) and ethylene-butene copolymer rubber (EBR).

The unsaturated carboxylic acid or its derivative used as the grafting agent in the present invention includes acrylic acid,
Examples thereof include methacrylic acid, crotonic acid, isocrotonic acid, fumaric acid, maleic acid, and the like, or derivatives thereof, with maleic acid or its derivatives being preferred. Maleic acid or a derivative thereof includes maleic acid, maleic anhydride, a salt of maleic acid and other derivatives. Examples of maleic acid salts include maleic acid monoamide, maleic acid diamide, maleic acid-N-monoethylamide,
Maleic acid-N, N-diethylamide, maleic acid-N
-Monobutylamide, maleic acid-N, N-dibutyramide and the like can be mentioned. Examples of maleic acid derivatives include maleimide, N-butylmaleimide, N-phenylmaleimide and the like. These are usually used alone, but two or more kinds can be used in combination. Of these, maleic anhydride is preferably used. The amount of the maleic acid used is preferably 0.1 to 20 parts by weight with respect to 100 parts by weight of the polyolefin in order to obtain a modified polyolefin having a good high graft ratio. If it is less than 0.1 part by weight, the effect of modification is small, and if it exceeds 20 parts by weight, the original properties as a polyolefin are impaired.

In the present invention, it is essentially important to carry out the grafting in the presence of divinylbenzene.
Divinylbenzene is 0 for 1 part by weight of maleic acids.
1 to 1 part by weight, preferably 0.2 to 0.8 part by weight,
If the amount is less than 0.1 part by weight, the graft ratio cannot be improved, the effect of improving the adhesiveness and moldability is small, and the effect of the present invention cannot be sufficiently exhibited. If it exceeds 1 part by weight, gelation of the modified polyolefin will proceed, which will adversely affect the physical properties of the obtained polyolefin and will not exhibit sufficient performance when used as a modifier.

Grafting can be carried out according to a known method except that divinylbenzene is present in the above proportion. As a method for such grafting, a solution method or a melt-kneading method is known, but the solution method requires a graft reaction and separation of a solvent after the reaction, which complicates the manufacturing process and apparatus, and thus the method of the present invention A melt-kneading method, which has simple steps and apparatus, is preferably used.

In the melt-kneading method, polyolefin, the above-mentioned unsaturated carboxylic acids, divinylbenzene, and a radical reaction initiator are used, and these components are charged into a melt-kneading apparatus such as a single-screw extruder or a twin-screw extruder to obtain 150 ~ 30
The modified polyolefin is obtained by kneading for about 0.1 to 20 minutes while heating and melting at a temperature of 0 ° C., preferably 180 to 250 ° C. The content of the radical reaction initiator is 0.001 to 5 parts by weight based on 100 parts by weight of the polyolefin,
It is preferably 0.01 to 3 parts by weight.

Examples of the radical reaction initiator include dialkyl peroxides such as di-t-butyl peroxide, dicumyl peroxide and t-butylcumyl peroxide, benzoyl peroxide,
Diacyl peroxides such as lauroyl peroxide, octanoyl peroxide and acetyl peroxide, carboxylic acid peroxides such as peroxybenzoic acid and peroxyacetic acid, ester peroxides such as t-butylperoxybenzoic acid and t-butylperoxypivalate. Or various organic peroxides such as various hydroxyperoxides, peroxyketals, ketone peroxides, 2,5-dimethyl-2,5-di-t-butylperoxyhexyne and inorganic peroxides, azobisisobutyrate. Diazo compounds such as ronitrile are used.
Alternatively, ultraviolet rays or radiation may be applied to generate radicals.

Various conditions such as the reaction temperature, the reaction time, the solvent in the solution method, the kneading method in the melt-kneading method and the like can be appropriately changed depending on the polyolefin used and the amount thereof.

[0017]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples. Examples 1 to 5 and Comparative Examples 1 to 4 polypropylene (melt flow rate (MFR, 230
C., 2.16 kg load) 1.0 g / 10 min) 100 parts by weight of maleic anhydride, divinylbenzene and organic peroxide (2,5-dimethyl-2,5-di-sha-butyl-peroxyhexyne): Product name Perhexyne 25B; manufactured by NOF CORPORATION is dry-blended at the ratio shown in Table 1, and then melted using a 58 mmφ twin-screw extruder at a cylinder temperature setting of 200 ° C and a screw rotation speed of 200 rpm. The polypropylene was modified by kneading. Melt flow rate (MF of the obtained modified polypropylene
R, 230 ° C., 2.16 kg load) is shown in Table 1. In this case, the unreacted monomer is recovered from the extruder vent.

[0018]

[Table 1]

As shown in the results of Table 1, the modified polyolefin obtained by adding divinylbenzene according to the present invention has no decrease in the molecular weight, and the maleic anhydride addition rate is low even if the added amount of maleic anhydride is small. It can be seen that the addition of divinylbenzene improves the efficiency of grafting.

[0020]

According to the process for producing a modified polyolefin of the present invention, when a polyolefin is graft-polymerized with an unsaturated carboxylic acid or a derivative thereof in the presence of divinylbenzene, a specific amount of divinylbenzene is used for extrusion. By melt-kneading with a machine, it is possible to produce a modified polyolefin having a high graft ratio, which is difficult to gel by a conventional melt-kneading method without gelation.
As a result, the function of the different polymer as a compatibilizing agent and the adhesiveness are improved, and it can be used as a useful compatibilizing agent or adhesive, and it can replace the conventional solution method using a solvent. A good modified polyolefin can be produced by a simple method such as a production process and an apparatus.

Claims (4)

[Claims] 1. A method for producing a modified polyolefin by graft-polymerizing an unsaturated carboxylic acid or a derivative thereof onto a polyolefin, to 100 parts by weight of the polyolefin,
0.1 to 20 parts by weight of unsaturated carboxylic acid or its derivative, and 0.1 to 1 part by weight of divinylbenzene to 1 part by weight of unsaturated carboxylic acid or its derivative, unsaturated carboxylic acid-modified polyolefin. Manufacturing method. 2. The method for producing a modified polyolefin according to claim 1, wherein the graft polymerization reaction is carried out using an extruder in the production of the modified polyolefin. 3. The method for producing a modified polyolefin according to claim 1, wherein the polyolefin is a polypropylene resin. 4. The method for producing a modified polyolefin according to claim 1, wherein the unsaturated carboxylic acid or its derivative is maleic acid or its derivative.