JPH07206946A - Production of modified low-molecular polyethylene polymer - Google Patents

Abstract

PURPOSE:To easily obtain a modified low-molecular polyethylene polymer having controlled viscosity without generating gelatinized material by modifying a low-molecular polyethylene polymer with an unsaturated dicarboxylic acid in the presence of a specific alpha-olefin. CONSTITUTION:(A) A low-molecular polyethylene and/or ethylene.alpha-olefin copolymer (preferably having an ethylene unit content of >=20 wt.% and a weight- average molecular weight of 10,000-50,000) is reacted with (B) an unsaturated dicarboxylic acid (preferably maleic anhydride) in the presence of (C) a radical generator (preferably di-t-butyl peroxide or dicumyl peroxide). The above reaction is carried out in the presence of (D) a 6-36C alpha-olefin (preferably 1-dodecene). The amounts of the components B, C and D are preferably 0.5-15wt.%, 0.2-1.5wt.% and 8-50wt.% based on the component A, respectively. The ethylene.a-olefin copolymer of the component A is preferably an ethylene propylene copolymer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a modified low molecular weight polyethylene polymer useful as a modifier for resins. More specifically, it relates to a method for producing low-molecular-weight polyethylene and / or ethylene / α-olefin copolymer modified with unsaturated dicarboxylic acids.

[0002]

When a low molecular weight polyethylene and / or ethylene / α-olefin copolymer is reacted with an unsaturated dicarboxylic acid in the presence of a radical generator, if the reaction is not controlled, the melt viscosity of the reaction product is It rises and crosslinks and gels are formed. For this reason, conventionally, the technique for controlling the melt viscosity in the reaction to obtain a reaction product free of cross-linking or gelation is (1) removing oxygen from the reaction vessel to reduce the oxygen concentration to less than 5 ppm, preferably less than 2 ppm. A method of carrying out the reaction (eg US Pat. No. 4,028,436),
(2) A method of performing a reaction in the presence of a thiol-based chain transfer agent (for example, JP-A-58-500813) is known.

[0003]

However, in the above technique (1), it is very difficult to maintain the oxygen concentration in the reaction vessel below 5 ppm on an industrial scale. Further, in the technique (2), the thiol chain transfer agent gives off a bad odor, and it is necessary to take an odor countermeasure in the manufacturing facility. Further, even after removing the thiol-based chain transfer agent by stripping, an offensive odor remains in the product, which is an unfavorable drawback.

[0004]

The present inventors have arrived at the present invention as a result of extensive studies to solve these problems. That is, in the present invention, low molecular weight polyethylene and / or ethylene / α-olefin copolymer (A) is reacted with an unsaturated dicarboxylic acid (C) in the presence of a radical generator (B) to obtain an acid-modified low molecular weight. In the method for producing polyethylene and / or low molecular weight ethylene / α-olefin copolymer (A1), the reaction is carried out with 6 carbon atoms.
~ 36 α-olefin (D) is present.

The low molecular weight polyethylene and / or ethylene / α-olefin copolymer (A) used in the present invention includes polyethylene resins [high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, etc. ], A copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms [ethylene / propylene copolymer, ethylene / propylene / diene copolymer, ethylene / 1-butene copolymer, ethylene / 1-hexene copolymer] Polymer, ethylene / 4-methyl-1-pentene copolymer, etc.]. The (co) polymer may be crystalline or amorphous. Of these, preferred are low molecular weight polyethylene resins and ethylene / propylene copolymers.

The content of ethylene units in (A) is usually 20.
It is more than weight%. When the content of ethylene units is less than 20%, problems such as increase in melt viscosity of the modified product and generation of gelled product do not usually occur.

(A) is obtained by a polymerization method or a thermal degradation method of a high molecular weight polyethylene and / or an ethylene / α-olefin copolymer. What is obtained by the thermal degradation method is preferable because it is easily modified by (C). The weight average molecular weight of (A) by the thermal degradation method is, for example, 10
A method of thermally degrading a high-molecular-weight polyethylene of 50,000 to 500,000 and / or an ethylene / α-olefin copolymer at 300 to 450 ° C. for 0.5 to 10 hours in an inert gas (for example, a special method). Described in the specification of Kaihei 3-62804).

The weight average molecular weight of (A) is usually 2,000.
0 to 100,000, preferably 5,000 to 60,0
00, and more preferably 10,000 to 50,000. When the weight average molecular weight of (A) is less than 2,000,
The mechanical properties of the resin to be added are lower than those without addition,
If it exceeds 100,000, it becomes difficult to add unsaturated dicarboxylic acids, and the effect as a modifier decreases. The weight average molecular weight can be determined by a high temperature gel permeation chromatography (GPC) method.

Examples of the radical generator (B) used in the present invention include organic peroxides. As the organic peroxide, one generally used as a radical polymerization initiator can be used, and one having a half-life at 150 ° C. of 1 minute or more is usually used. Specifically, a ketone peroxide such as methyl ethyl ketone peroxide; di-t-
Butyl peroxide, dicumyl peroxide, 2,5-
Dialkyl peroxides such as dimethyl-2,5-di (t-butylperoxy) hexane; peroxyesters such as t-butylperoxybenzoate, hydroperoxides such as diisopropylbenzene hydroperoxide, and the like. , These alone or 2
Used in combination of two or more species. Of these, preferred are di-t-butyl peroxide and dicumyl peroxide.

The amount of (B) is usually 0.05 to 2.0% by weight, preferably 0.2 to 1.5% by weight, based on the weight of (A). If the amount of (B) is less than 0.05% by weight, unsaturated dicarboxylic acids are difficult to add, and if it exceeds 2.0% by weight, the main chain is cleaved, resulting in a decrease in the molecular weight of (A1).

The unsaturated dicarboxylic acids (C) used in the present invention include unsaturated dicarboxylic acids (maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid and their anhydrides), unsaturated dicarboxylic acid half. Examples thereof include esters or all esters (butyl maleate, methyl maleate, dibutyl maleate, butyl itaconate, etc.), and these can be used alone or in combination of two or more kinds. Of these, particularly preferred is maleic anhydride.

The amount of (C) is usually 0.1 to 25% by weight, preferably 0.5 to 15% by weight, based on the weight of (A). If the amount of (C) is less than 0.1% by weight, the degree of modification will be low and the effect as a resin modifier will be reduced, and if it exceeds 25% by weight, the viscosity will be high and workability will be poor, resulting in resin modification. The effect as an agent also decreases.

As the α-olefin (D) having 6 to 36 carbon atoms in the present invention, a linear α-olefin and / or an α-olefin having a branched chain is used. Specifically, hexene-1, octene-1, nonene (nonene-
1, propylene trimer), decene-1, dodecene (dodecene-1, propylene tetramer), tetradecene-1, pentadecene (pentadecene-1, propylene pentamer),
Hexadecene-1, Octadecene-1, Eicosene-
1, α-olefin mixture having 20 or more carbon atoms, and the like, and these can be used alone or in combination of two or more kinds. Of these, particularly preferred is 1-
This is Dodecen.

The amount of (D) is usually 2 to 200% by weight, preferably 8 to 50% by weight, based on the weight of (A).
If the amount of (D) is less than 2% by weight, the melt viscosity will be high and the effect of suppressing the formation of a gel will be poor, and if it is used in excess of 200% by weight, there will be no further gelation suppressing effect and it is uneconomical.

The reaction between (A) and (C) can be carried out by either a solution method or a melting method.

In the case of the solution method, (A1) can be obtained by heating and dissolving (A), (C) and (D) in an organic solvent and heating in the presence of (B). As the organic solvent used, a hydrocarbon having 6 to 12 carbon atoms, a halogenated hydrocarbon, or the like can be used. The reaction temperature may be a temperature at which the polyolefin used is dissolved,
It is usually 110 to 250 ° C. The pressure is atmospheric pressure or, if necessary, pressure is applied.

In the case of the melting method, (A1) can be obtained by mixing (A), (C) and (D) with (B) and then kneading and reacting under melting conditions.
This kneading method can be carried out using various kneaders such as an extruder, a Brabender, a kneader or a Banbury mixer. The kneading temperature is preferably in the range of not lower than the melting point of the low molecular weight polyethylene and / or ethylene / α-olefin copolymer (A) used to not higher than 300 ° C.

In the solution method or the melting method, the organic solvent and unreacted (C) and (D) can be removed by a method such as vacuum distillation and solvent extraction.

If necessary, additives such as antioxidants can be added in the above production method.

When the production method of the present invention is used, the melt viscosity can be easily controlled without controlling the oxygen concentration to an extremely small amount, and without using a thiol which gives off a bad odor, and there is no gelation (A1). ) Can be obtained.

The acid-modified low molecular weight polyethylene and / or ethylene / α-olefin copolymer (A1) obtained by the method of the present invention is useful as a compatibilizing agent for polymer alloys. The target polymer alloys are polyolefin / polyamide type, polyolefin / polyester type,
Polyolefin / polyimide system and polyolefin /
A polyimide amide type is mentioned, and the polymer alloy is preferably used for outer panels for automobiles, housings for home electric appliances and OA equipment, and the like. Further, (A1) obtained by the method of the present invention is a low temperature impact strength improver such as a polyolefin resin, a polyamide resin, a polyester resin, a polyimide resin, a moldability improver, a dispersant for a pigment or a feeler, and a coating. It is also useful as a modifier for resin such as a improver of adhesiveness and adhesiveness.

[0022]

The present invention will be further described with reference to the following examples.
The present invention is not limited to this. In the following, "part" means part by weight and "%" means% by weight.

Production Example 1 Ethylene / propylene = 5 in a 3 L 4-necked Kolben equipped with a nitrogen inlet pipe, a thermometer, an exhaust gas outlet pipe and a stirrer.
0/50 (wt%) ethylene / propylene copolymer rubber (hereinafter referred to as EPR) [trade name “EP-92
1 ", manufactured by Japan Synthetic Rubber Co., Ltd.] 1,500 g was cut into small blocks and charged in a nitrogen atmosphere. After that, nitrogen was continuously aerated in the Kolben until the end of the thermal degradation reaction. Next, heat with a mantle heater, raise the temperature, and stir 350
Thermal degradation was performed at 2.5 ° C. for 2.5 hours. Then heat degradate 20
Low molecular weight EPR after cooling to 0 ° C
Got The physical properties are shown in Table 1.

Production Example 2 A low molecular weight EPR was obtained in the same manner as in Production Example 1 except that the thermal degradation reaction was carried out at 355 ° C. for 2.5 hours. The physical properties are shown in Table 1.
Shown in.

Production Example 3 Instead of "EP-921" in Production Example 1, ethylene / propylene = 78/22 (wt%) EPR [trade name "EP-912P", manufactured by Nippon Synthetic Rubber Co., Ltd.] was used. A low molecular weight EPR was obtained in the same manner as in Production Example 1 except that the same amount was used and the thermal degradation reaction was carried out at 355 ° C. for 3.5 hours. The physical properties are shown in Table 1.

Production Example 4 A low molecular weight EPR was obtained in the same manner as in Production Example 3 except that the thermal degradation reaction was carried out at 350 ° C. for 1 hour. The physical properties are shown in Table 1.

Production Example 5 In place of "EP-921" in Production Example 1, low-density polyethylene [trade name "Sumikasen G806", manufactured by Sumitomo Chemical Co., Ltd.] was used in the same amount, and the thermal degradation reaction was carried out at 350 ° C. In 2
A low-molecular-weight polyethylene was obtained in the same manner as in Production Example 1 except that the time was changed. The physical properties are shown in Table 1.

Production Example 6 A low molecular weight polyethylene was obtained in the same manner as in Production Example 5 except that the thermal degradation reaction was carried out at 350 ° C. for 3.5 hours. The physical properties are shown in Table 1.

Example 1 1,000 g of low molecular weight EPR obtained in Production Example 1, 55 g of maleic anhydride and 100 g of dodecene-1 [trade name "Dialen-12", manufactured by Mitsubishi Kasei Co., Ltd.] were dropped into a nitrogen introducing tube. A 3 L autoclave equipped with a funnel, thermometer and stirrer was charged. After replacing the inside of the autoclave with nitrogen, heat it with a mantle heater and raise the temperature to 180
Melted at ° C. Then 5 g of di-t-butyl peroxide
Was added from a dropping funnel and reacted at 180 ° C. for 1 hour. After the reaction, the temperature is set to 190 ° C. and the pressure inside the system is reduced,
Stripping is performed under a reduced pressure of 5 Torr for 1 hour to obtain 1
After cooling to 60 ° C., the product was taken out to obtain a maleic anhydride-modified low molecular weight EPR. The physical properties are shown in Table 1.

Example 2 1,000 g of low molecular weight EPR obtained in Production Example 2, 130 g of maleic anhydride, 150 g of nonene (propylene trimer) [trade name "Nonene", manufactured by Esso Kagaku KK] and di-t. -Except that 10 g of butyl peroxide was used
The reaction was carried out in the same manner as in Example 1 to obtain a maleic anhydride-modified low molecular weight EPR. The physical properties are shown in Table 1.

Example 3 1,000 g of low molecular weight EPR obtained in Production Example 3, 250 g of maleic anhydride, 500 g of tetradecene-1 [trade name "Dialen-14", manufactured by Mitsubishi Kasei Co., Ltd.] and di-t-butyl. The reaction was performed in the same manner as in Example 1 except that 15 g of peroxide was used to obtain a maleic anhydride-modified low molecular weight EPR. The physical properties are shown in Table 1.

Example 4 1,000 g of the low molecular weight EPR obtained in Production Example 4, 10 g of maleic anhydride, Octene-1 [trade name "Dialen-8", manufactured by Mitsubishi Kasei Co., Ltd.] and di-t-butyl. The reaction was carried out in the same manner as in Example 1 except that 2 g of peroxide was used, and maleic anhydride-modified low molecular weight EPR was used.
Got The physical properties are shown in Table 1.

Example 5 1,000 low molecular weight polyethylene obtained in Production Example 5
g, maleic anhydride 65 g, "Dialen-12" 10
The reaction was performed in the same manner as in Example 1 except that 0 g and 10 g of dicumyl peroxide were used to obtain maleic anhydride-modified low molecular weight polyethylene. The physical properties are shown in Table 1.

Example 6 Low molecular weight polyethylene 1,000 obtained in Production Example 6
g, maleic anhydride 150 g, "Dialen-12" 1
The reaction was carried out in the same manner as in Example 1 except that 00 g and dicumyl peroxide 10 g were used to obtain a maleic anhydride-modified low molecular weight polyethylene. The physical properties are shown in Table 1.

Comparative Example 1 A maleic anhydride-modified low molecular weight EPR was obtained in the same manner as in Example 1 except that "Dialene-12" was not used. The physical properties are shown in Table 2.

Comparative Example 2 A maleic anhydride-modified low-molecular-weight polyethylene was obtained in the same manner as in Example 1, except that "Dialen-12" was not used in Example 5. The physical properties are shown in Table 2.

[0037]

[Table 1] Molecular weight Mw; by gel permeation chromatography (GPC) method. Gelled substance: visually inspected for the presence or absence of insoluble matter in hot xylene.

[0038]

[Table 2]

As is apparent from Tables 1 and 2, the acid-modified low-molecular-weight polyethylene and / or ethylene / α-olefin copolymer obtained by the production method of the present invention has a small increase in melt viscosity due to acid modification. There is no gel formation.

Example 7 80 parts of nylon 6 [trade name "Amilan CM1021", manufactured by Toray Industries, Inc.], 10 parts of EPR "EP-921" and the maleic anhydride-modified low molecular weight EPR obtained in Example 1
Cylinder-Temperature 280 with 10 parts using a twin-screw extruder
After blending at 0 ° C., injection molding was performed to obtain a polymer alloy test piece. The Izod impact strength of this test piece was measured and found to be 8.0 kgg / cm notched (25 ° C.).

Comparative Example 3 The Izod impact strength of nylon 6 alone under the same conditions was 1.0 Kgcm / cm notched (25 ° C.).
From this result, it was found that the maleic anhydride-modified low molecular weight EPR obtained by the method of the present invention is an excellent impact strength improver.

Example 8 Nylon 66 [trade name "Leonar 1300S", manufactured by Asahi Kasei Co., Ltd.] 65 parts, polypropylene [trade name "Ube Polypro J609H", manufactured by Ube Industries, Ltd.] 30% by weight and obtained in Example 5 5 parts of maleic anhydride-modified low-molecular-weight polyethylene was used at a cylinder temperature of 28
After blending at 0 ° C., injection molding was performed to obtain a polymer alloy test piece. The test piece was broken in liquid nitrogen, and the fracture surface was observed by an electron microscope to measure the dispersed particle size of polypropylene dispersed in nylon to evaluate the compatibility. As a result, the dispersed particle diameter of polypropylene was 1 μm or less, and the dispersibility was good and the compatibilizing ability was excellent.

Comparative Example 4 A polymer alloy test piece was prepared and compatibility was evaluated in the same manner as in Example 8 except that maleic anhydride-modified low molecular weight polyethylene was not added. As a result, the dispersed particle size of polypropylene dispersed in nylon is 25 to 30.
It was found to be low, and the compatibility as a polymer alloy was low.

[0044]

EFFECT OF THE INVENTION By using the production method of the present invention, the oxygen concentration in the reaction system can be controlled to an extremely small amount of 5 ppm or less, and a thiol chain transfer agent with a strong odor is not used, and acid modification without gelation is achieved. A low molecular weight polyethylene (co) polymer can be easily obtained. The acid-modified low-molecular-weight polyethylene (co) polymer obtained by the production method of the present invention has the following effects as a resin modifier,
It is extremely useful in industry. (1) It has excellent compatibilizing ability as a compatibilizing agent for polymer alloys. (2) It is effective in improving the impact strength of various resins at low temperatures. (3) It exhibits excellent effects when used as a fluidity improver during molding of various resins. (4) It exhibits excellent effects when used as a dispersant when mixing pigments, feelers and the like into various resins. (5) When used by mixing with polyolefins such as polyethylene and polypropylene, the paintability of the paint on the resin surface,
It also improves the adhesiveness to other films when formed into a film.

Claims (6)

[Claims] 1. A low molecular weight polyethylene and / or ethylene / α-olefin copolymer (A) is reacted with an unsaturated dicarboxylic acid (C) in the presence of a radical generator (B) to give an acid-modified low molecular weight. A process for producing polyethylene and / or a low molecular weight ethylene / α-olefin copolymer (A1), characterized in that the reaction is carried out in the presence of an α-olefin (D) having 6 to 36 carbon atoms. Law. 2. The polyethylene content in (A) is 20% by weight or more, and the weight average molecular weight of (A) is 2,000.
The production method according to claim 1, which is 0 to 100,000. 3. The amount of (C) is based on the weight of (A)
The manufacturing method according to claim 1 or 2, which is 0.1 to 25% by weight. 4. The amount of (D) is based on the weight of (A)
The production method according to claim 1, which is 2 to 200% by weight. 5. The method according to claim 1, wherein (A) is obtained by thermally degrading polyethylene and / or an ethylene / α-olefin copolymer. 6. A resin modifier comprising (A1) obtained by the method according to any one of claims 1 to 5.