JPH06199967A - Method for modifying polyolefin - Google Patents

Abstract

PURPOSE:To efficiently modify a polyolefin into a modified product large in the amount of an addition-reacted monomer and excellent in adhesivity, compatibility, and printability by dividing a reaction initiator and a functional group- having monomer into plural portions, respectively, gradually adding the portions to a polyolefin and reacting the monomer with the polyolefin in the presence of a solvent. CONSTITUTION:In the case of modifying a polyolefin by dividing a reaction initiator such as benzoyl peroxide and a functional group-having monomer such as maleic anhydride into two or more portions, respectively, gradually adding the portions to the polyolefin and reacting the monomer with the polyolefin in the presence of a solvent, the next addition is performed after the concentration of the reaction initiator in the reaction solution becomes 1/4 or lower of its concentration at the time of its addition to the polyolefin 40-70 pts.wt. of the functional group-having monomer and 4-7 pts.wt. of the reaction initiator are preferably added to 100 pts.wt. of the polyolefin for each addition.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for modifying a polyolefin. More specifically, it relates to a method for modifying a polyolefin in which the addition amount of the monomer is increased by adding the monomer in a divided manner when modifying the polyolefin with a monomer having a functional group in the presence of a solution.

[0002]

2. Description of the Related Art In recent years, a method of modifying a polyolefin with a monomer having a functional group has been carried out in order to impart functions such as adhesiveness, paintability and compatibility to polyolefin. Generally, when a monomer having a functional group is added to a polyolefin for modification, a method is known in which a reaction initiator is used in the presence of a solvent or without a solvent for modification. As a method of modifying a polyolefin with a monomer in the presence of a solvent, a method of dissolving the polyolefin and the monomer in the solvent and then adding a catalyst dissolved in a small amount of the solvent to the system to carry out the reaction (Japanese Patent Publication No. 44-15422) A method of dissolving a polyolefin in a halogenated hydrocarbon solvent and then adding a monomer and a reaction initiator (JP-A-48-28092).
No.) etc.

[0003]

Usually, when it is attempted to increase the amount of the monomer added in the above method, the reaction temperature is raised or the amount of the monomer having a functional group is increased. However, when these methods are used, in the case of the former, there are problems that a solid viscous product presumed to be a homopolymer of a monomer having a functional group is generated, or the evaporation of the solvent becomes remarkable, and the latter. In the above case, there was a problem that the addition amount was the maximum at some points, and the addition amount was more than that, the conversely the addition amount decreased. An object of the present invention is to solve these problems and provide a method for modifying a polyolefin in which the amount of the modifying monomer added is large.

[0004]

Means for Solving the Problems As a result of intensive studies conducted by the present inventors in view of the above-mentioned object, the inventors have found that a monomer having a functional group and a reaction initiator are added twice or more in a divided manner for modification. The present invention has been accomplished by finding that a modified polyolefin having a high addition amount of a monomer can be obtained. That is, the first aspect of the present invention is to use a reaction initiator in the presence of a solvent,
In a reaction for adding a monomer having a functional group to a polyolefin and modifying the same, a reaction initiator and the monomer are added in two or more divided portions, which is a method for modifying a polyolefin. In the second aspect of the present invention, when the above-mentioned divided addition is carried out, the next addition is carried out after the concentration of the reaction initiator in the reaction solution becomes ¼ or less of the concentration reached by the immediately preceding addition. This is a method for modifying a polyolefin. The third aspect of the present invention is characterized in that 40 to 70 parts by weight of the monomer having a functional group and 4 to 7 parts by weight of the reaction initiator are added at one time based on 100 parts by weight of the polyolefin before the reaction. It is the above-mentioned modification method.

Examples of the polyolefin of the present invention include ultra low density polyethylene, high pressure low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene; ethylene-propylene copolymer rubber, ethylene-propylene-diene copolymer. Olefin rubber such as polymer rubber and ethylene-butene-1 copolymer rubber; ethylene-vinyl ester copolymer such as ethylene-vinyl acetate copolymer, ethylene-alkyl acrylate copolymer, ethylene-methacrylic acid Ethylenic copolymers such as copolymers with ethylene-α, β-carboxylic acid or its derivatives such as alkyl ester copolymers; polypropylene-based polymers such as polypropylene and propylene-ethylene copolymers; polybutene-based polymers Etc.

Among the above-mentioned polyolefins, the modification method of the present invention is effective when a polyolefin having a tertiary carbon atom such as polypropylene, which undergoes severe cleavage of the polymer main chain when modified without a solvent, is used. Remarkable. As the polypropylene, any of a random polymer, a block polymer, a homopolymer and the like can be used.

As the monomer having a functional group used for modification in the present invention, e1: a carboxylic acid group, a carboxylic acid ester group or an acid anhydride group-containing monomer, e2: an epoxy-containing monomer, e3: a hydroxyl group-containing monomer, e4: Amine-containing monomer, e5: alkenyl cyclic iminoether derivative, e6: polyfunctional monomer, e7: organic titanate compound, e8: unsaturated organosilane compound,
e9: At least one compound selected from the group consisting of aluminum-based coupling agents.

Examples of the e1: carboxylic acid group, carboxylic acid ester group or acid anhydride group-containing monomer used in the present invention include α, β-unsaturated dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid and itaconic acid; acrylic acid Unsaturated carboxylic acids such as methacrylic acid, furanic acid, crotonic acid, vinyl acetic acid, pentenoic acid; esters and anhydrides of these α, β-unsaturated dicarboxylic acids or unsaturated monocarboxylic acids.

E2: Epoxy-containing monomers include glycidyl acrylate, glycidyl methacrylate, itaconic acid monoglycidyl ester, butene tricarboxylic acid monoglycidyl ester, butene tricarboxylic acid diglycidyl ester, butene tricarboxylic acid triglycidyl ester; α-chloroallyl, Glycidyl esters such as maleic acid, crotonic acid, fumaric acid; glycidyl ethers such as vinyl glycidyl ether, allyl glycidyl ether, glycidyl oxyethyl vinyl ether, styrene-p-glycidyl ether; p-glycidyl styrene, etc. Preferable examples include glycidyl methacrylate and allyl glycidyl ether.

E3: Examples of the hydroxyl group-containing monomer include 1-hydroxypropyl acrylate, 1-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, hydroxyethyl acrylate and hydroxyethyl methacrylate.

E4: As amine-containing monomers, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate,
Examples include tertiary amine-containing monomers such as diethylaminoethyl methacrylate, dibutylaminoethyl acrylate and dibutylaminoethyl methacrylate.

The e5: alkenyl cyclic imino ether derivative is a compound represented by the following structural formula 1.

[0013]

[Chemical 1]

Here, n is 1, 2 or 3, preferably 2 or 3, and more preferably 2. R ¹ , R ² , R ³ and R represent a C _{1 to} C ₁₂ inactive alkyl group or a hydrogen atom, and the alkyl group may have an inactive substituent. The term "inert" as used herein means that the graft reaction and the function of the product are not adversely affected. Further, R ¹ , R ² , R ³ and R do not all have to be the same. Preferably, R ¹ , R ² and R are hydrogen atoms and R ³ is a hydrogen atom or a methyl group. That is, 2-vinyl- or 2-isopropenyl-2-oxazoline or 2-vinyl- or 2-isopropenyl-5,6
-Dihydro-4H-1,3-oxazine. These may be used alone or as a mixture. Among these, 2-vinyl- or 2-isopropenyl-2-oxazoline is particularly preferable.

E6: As the polyfunctional monomer, polyfunctional methacrylate monomers represented by trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, etc .; divinylbenzene, triallyl isocyanurate,
Polyfunctional vinyl monomers typified by diallyl phthalate and vinyl butyrate; bismaleimides typified by N, N'-m-phenylene bismaleimide and N, N'-ethylene bismaleimide; p-quinone dioxime And other dioximes.

E7: Tetra (2,2-diallyloxymethyl-1-butyl) bisbis as an organic titanate compound
(Di-tridecyl) phosphite titanate, isopropyl dimethacryl isostearoyl titanate, isopropyl isostearoyl diacryl titanate, tetraisopropyl titanate, tetra-n-butyl titanate, tetrakis (2-ethylhexoxy) titanate, titanium lactate. Examples thereof include ammonium salts.

E8: As the unsaturated organosilane compound,
Examples thereof include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetylsilane, vinyltrichlorosilane and the like.

E9: Examples of the aluminum-based coupling agent include acetoalkoxyaluminum diisopropylate.

Among the monomers having the above functional groups,
Maleic anhydride is particularly preferable because it is highly effective, inexpensive and easily available. If the amount of the monomer having these functional groups is too large, a by-product is generated by the polymerization of the monomers, and if the amount is too small, it is ineffective.
It is desirable to finally use 80 to 300 parts by weight with respect to 0 parts by weight.

As the reaction initiator of the present invention, all known radical generators can be used. For example, benzoyl peroxide, lauryl peroxide, dicumyl peroxide, t-butyl hydroperoxide, α,
α-bis (t-butylperoxydiisopropyl) benzene, di-t-butylperoxide, 2,5-di- (t-
Butylperoxy) hexyne and other peroxides, azobisisobutyronitrile, 2,3-dimethyl-2,3-diphenylbutane, 2,3-diethyl-2,3-diphenylbutane, 2,3-diethyl -2,3-di (p-methylphenyl) butane, 2,3-diethyl-2,3-di (bromophenyl) butane and the like can be mentioned. Of these, dicumyl peroxide, which has a slow reaction and is highly safe, is desirable.

If the amount of the above-mentioned reaction initiator used in the present invention is too large, the polyolefin itself will be excessively cleaved or crosslinked, and if it is too small, sufficient modification will not occur. 21 parts by weight, preferably 12 to 18 parts by weight.

In the method of the present invention, both the above-mentioned monomer having a functional group and the reaction initiator are added in two or more portions. Even if only one of them is divided and added, sufficient denaturation is not performed. At this time, it is preferable that the addition amount of one time is 40 to 70 parts by weight and the reaction initiator is 4 to 7 parts by weight with respect to 100 parts by weight of the polyolefin before the reaction. If the amount added is too small, it will not react sufficiently, and if it is too large, it will cause cleavage and crosslinking of the main chain and will be lost from the system due to evaporation and decomposition, which is uneconomical.

In the present invention, the method of adding the monomer having a functional group and the reaction initiator is arbitrary, but the particularly preferable addition method is as follows. In the case of a liquid, the monomer having a functional group may be dissolved together with the polyolefin as it is, but in the case of a solid, it should be liquefied once under heat and pressure using an autoclave and then introduced into the reaction system. Is preferred. The reaction initiator is preferably added after being dissolved in the same solvent as that used for dissolving the polyolefin. In the present invention, it is important to add the monomer having the functional group and the reaction initiator in two or more times as described above, but the monomer having the functional group and the reaction initiator are added after the second time. In this case, the concentration of the reaction initiator in the reaction solution is 1 / of the concentration of the same reaction initiator reached by the immediately preceding addition (the total of the added amount and the residual amount).
After the amount is reduced to 4 or less, preferably 1/6 or less, the next addition is performed. If the second and subsequent additions are performed while the concentration of the reaction initiator is higher than the above ¼, the effect of improving the addition amount of the monomer is small. The reaction temperature is 100 to 200 ° C, preferably 120 to 150 ° C.

The solvent used in the present invention may be any solvent which dissolves polyolefin, that is, any solvent which is a good solvent, but in view of economical efficiency and safety, it is a hydrocarbon solvent, particularly xylene or toluene. Is preferred. The concentration when dissolving the polyolefin is 10
It is 10 to 60 g, preferably 20 to 30 g per 0 ml.

Next, an example of a method of modifying a polyolefin by adding a monomer having a functional group to a polyolefin in the presence of a solution according to the present invention will be described. First, a solvent is added and dissolved while heating the polyolefin. At this time, since the Weissenberg effect occurs when the amount of the polyolefin dissolved at a time exceeds a certain value, it is preferable to dissolve the polyolefin in two or more times. After the polyolefin is dissolved, a monomer having a functional group dissolved in a solvent and a reaction initiator are added to the solution. At this time, the temperature of the liquid is kept constant. As described above, the monomer having the functional group and the reaction initiator are added in two or more portions. At this time, if necessary, the evaporated monomer having a functional group is recovered. When adding after the second time, the addition is started after the concentration of the reaction initiator has decreased to a certain value or less as described above. The time interval for the divided addition varies depending on the conditions, but when dicumyl peroxide is used,
When the denaturation is carried out under the condition of ° C, it takes about 30 minutes. There is a method of removing the solvent by evaporation or the like in recovering the modified polyolefin after the completion of the reaction, but there is a concern that unreacted monomers may remain in the modified polyolefin, and therefore it is preferable to precipitate the so-called poor solvent.

[0026]

EXAMPLES The present invention will be shown below by examples, but the present invention is not limited to the examples. <Example 1> 500 ml of xylene (special grade reagent, manufactured by Kishida Chemical Co., Ltd.) and polypropylene (trade name: E110P, manufactured by Nippon Petrochemical Co., Ltd.) 1 in a 1-liter round bottom flask.
20 g, maleic anhydride (special grade reagent, Kishida Chemical Co., Ltd.)
(Manufactured by Mitsui Chemicals Co., Ltd.), and was thoroughly replaced with nitrogen. Next,
300 r using a motor (maximum torque 2 kg · cm, trade name: Three One Motor TYPE-600G, manufactured by Shinto Kagaku Co., Ltd.)
It was heated with a mantle heater while stirring at pm. The liquid temperature was set to 140 ° C. to completely dissolve polypropylene and maleic anhydride. Next, while maintaining the liquid temperature at 140 ° C., a solution in which 6 g of dicumyl peroxide (manufactured by NOF CORPORATION) was dissolved in 20 g of xylene was added dropwise thereto over 40 minutes. 2 hours and 20 minutes after dropping, the liquid temperature is 14
After allowing the reaction to proceed at 0 ° C., the concentration of dicumyl peroxide in the system was reduced to 1/16 or less of the total amount of 6 g added. Here, 74 g of maleic anhydride, which had been sufficiently replaced with nitrogen, was added to the reaction system, and then a solution of 6 g of dicumyl peroxide (same as above) dissolved in 20 g of xylene was added to 40 g of the solution.
It took minutes to drop. The reaction was completed by keeping the liquid temperature at 140 ° C. for 2 hours and 20 minutes after the dropping. Total reaction time is 6
It's time. Then, the liquid temperature was lowered to 80 ° C., 500 ml of acetone (manufactured by Nippon Petrochemical Co., Ltd.) was added to precipitate the modified polypropylene, and the polypropylene was recovered by filtration. Purification was carried out according to a conventional method using a large amount of acetone. The amount of maleic anhydride added to the modified polypropylene was measured by the IR method using a calibration curve prepared in advance (the same applies hereinafter). The results are shown in Table 1.

Example 2 The procedure of Example 1 was repeated, except that maleic anhydride and dicumyl peroxide were added once. The results are shown in Table 1.

Comparative Example 1 500 ml of xylene (special grade reagent, manufactured by Kishida Chemical Co., Ltd.) and polypropylene (trade name: E110P, manufactured by Nippon Petrochemical Co., Ltd.) 120 g, maleic anhydride (in a 1 liter round bottom flask) 148 g of special grade reagent (manufactured by Kishida Chemical Co., Ltd.) was added and the atmosphere was sufficiently replaced with nitrogen. Next, a motor (maximum torque 2 kg / cm, trade name: Three One Motor TYPE-600G, manufactured by Shinto Kagaku Co., Ltd.)
Was heated with a mantle heater while stirring at 300 rpm. The liquid temperature was set to 140 ° C. to completely dissolve polypropylene and maleic anhydride. Next, while maintaining the liquid temperature at 140 ° C., a solution in which 12 g of dicumyl peroxide (manufactured by NOF CORPORATION) was dissolved in 40 g of xylene was added dropwise thereto over 40 minutes. 2 hours after dropping
The liquid temperature was maintained at 140 ° C. for 0 minutes to complete the reaction. The reaction time is 3 hours in total. Then, the liquid temperature was lowered to 80 ° C., 500 ml of acetone (manufactured by Nippon Petrochemical Co., Ltd.) was added to precipitate the modified polypropylene, and the polypropylene was recovered by filtration. Purification was carried out according to a conventional method using a large amount of acetone. Table 1 shows the amount of maleic anhydride added to the obtained modified polypropylene.

<Comparative Examples 2 to 4> The same operation as in Comparative Example 1 was performed except that the amounts of maleic anhydride and dicumyl peroxide added were changed. The results are shown in Table 1.

<Comparative Example 5> The reaction time was changed to 6 hours,
The same operation as in Comparative Example 1 was performed. The results are shown in Table 1.

Comparative Example 6 The same as Comparative Example 1 except that maleic anhydride was not added to the polypropylene solution in advance, only maleic anhydride was sequentially added after the temperature was raised, and the total amount of dicumyl peroxide was added at 1 hour. The operation was performed. The results are shown in Table 1.

<Example 3> After the first addition of dicumyl peroxide, the reaction was allowed to proceed for 1 hour and 20 minutes, and the second time when the concentration of dicumyl peroxide in the system decreased to ⅛ or less of that at the time of addition. The same operation as in Example 1 was performed except that addition was performed. The reaction time is 5 hours in total. The results are shown in Table 1.

<Example 4> After the first addition of dicumyl peroxide, the reaction was allowed to proceed for 20 minutes, and when the concentration of dicumyl peroxide in the system was reduced to about 1/4 of the addition, the second addition was performed. The same operation as in Example 1 was carried out except that it was performed. The total reaction time is 4 hours. The results are shown in Table 1.

[0034]

EFFECTS OF THE INVENTION According to the present invention, a modified polyolefin having a high addition amount of a modifying monomer is obtained by using a relatively simple method in which a monomer having a functional group is added in a divided manner when modifying a polyolefin. be able to. The modified polyolefin of the present invention can be used as a resin having excellent adhesiveness, compatibility, printability, insulating property, affinity with a filler, etc. by itself or by blending with other resin.

[Table 1]

Claims (3)

[Claims] 1. In a reaction in which a monomer having a functional group is added to a polyolefin and modified by using a reaction initiator in the presence of a solvent, the reaction initiator and the monomer are added in two or more divided portions. A characteristic method for modifying a polyolefin. 2. When the reaction initiator is dividedly added, the concentration of the reaction initiator in the reaction solution is 1 / the concentration at the time of addition.
The method for modifying a polyolefin according to claim 1, wherein the following addition is carried out after the number becomes 4 or less. 3. The amount of the monomer having a functional group added at one time is 40 to 100 parts by weight of the polyolefin before the reaction.
70 parts by weight and 4 to 7 parts by weight of the reaction initiator, The method for modifying a polyolefin according to claim 1 or 2, wherein