JPH05247146A - Modification of polyolefin - Google Patents

Abstract

PURPOSE:To efficiently modify a polyolefin with a functional group-containing monomer by carrying out ready agitation for dissolution while avoiding occurrence of Weisenberg effect. CONSTITUTION:After dissolving a polyolefin in a solvent in a concentration lower than that where Weisenberg effect is substantially caused, the concentration of the polyolefin is increased by further adding the polyolefin thereto and modification is subsequently carried out by using a functional group-containing monomer.

Description

Detailed Description of the Invention

[0001]

[Industrial application] In recent years, many improvements have been made to polyolefins, such as adhesiveness, paintability, hydrophilicity, etc., to increase added value. There is a method of modifying the compound with a monomer having a functional group. The present invention relates to a method of dissolving a polyolefin in a solvent without substantially causing a normal stress called the Weissenberg effect when the above modification is performed in an organic solvent, and then performing the modification.

[0002]

2. Description of the Related Art Generally, as a method of modifying a polyolefin with a monomer, a method of modifying with or without a solvent in the presence of an organic peroxide is known. In the latter case, it is common to dissolve the polyolefin in an organic solvent and then add the monomer and the catalyst to the system to carry out the reaction. At this time, in the initial stage of the process of dissolving the polyolefin in the organic solvent, a normal stress called the Weisenberg effect is generated due to the rapid increase in viscosity, and the polyolefin is entangled with the stirring shaft to make stirring difficult. Further, as the dissolution progresses, the viscosity decreases, and at the stage of complete dissolution, the liquid viscosity becomes so small that practically no problem occurs. Figure 1
A method of generating the Weissenberg effect is schematically shown in FIG. That is, the Weissenberg effect is a kind of normal stress effect of viscoelastic liquid, and when the elastically deformed portion becomes large due to the constant shear flow, tension is generated in the streamline direction in addition to the shear stress, and in the direction perpendicular to this. Creates pressure. For example, in the cylindrical round bottom flask 1 as shown, when the stirring blade 2 is rotated, the central portion of the liquid surface 3 is pushed up around the stirring shaft 4.

When the polyolefin is industrially dissolved using a reactor of 2 to 5 m ³ , the above-mentioned temporary increase in viscosity poses a serious problem. Normally, the stirrers equipped in these reactors are designed for liquid viscosities of a few hundred poises or less, so a large load is applied to the stirrer when dissolving polyolefin, and excessive current is applied. Stirring stops or stirrer failure. In order to avoid this, usually, (1) load is suppressed by reducing the amount of polyolefin charged relative to the size of the reactor, (2) stirring is stopped when the viscosity increases, or stirring speed is increased. Is used.

[0004]

In the above, (1)
In the case of (1), the yield per batch is reduced, so that the economical efficiency is reduced, and in the case of (2), it takes a long time to dissolve because the stirring is stopped, and there is a problem that the polyolefin is deteriorated due to local heating. .. It is an object of the present invention to solve the above-mentioned problems and to establish a method of dissolving a polyolefin without substantially causing the Weissenberg effect and then performing a modification.

[0005]

Means for Solving the Problems The inventors of the present invention have made earnest studies as to a method for industrially and easily modifying a polyolefin that substantially avoids the Weisenberg effect due to an increase in viscosity, and as a result, divides and melts the polyolefin. The present invention has been accomplished by finding that the above problems can be solved by doing so. That is, the first aspect of the present invention is that "when modifying a polyolefin with a monomer having a functional group in the presence of a good solvent, the polyolefin is divided and added to the solvent to substantially produce the Weissenberg effect. It is a method of modifying a polyolefin, which is characterized in that it is completely dissolved without being subjected to a modification and then modified, and the second of the present invention is, "when the polyolefin is divided and added to a solvent, it is substantially Weissenberg. After dissolving the polyolefin in the solvent at a concentration lower than the concentration at which the effect is produced, further adding polyolefin to increase the polyolefin concentration,
The method for modifying a polyolefin according to claim 1, characterized in that the modification is performed thereafter. The third aspect of the present invention is:
The method according to claim 1 or 2, wherein xylene and polypropylene are used as the solvent and the polyolefin, respectively, and the polypropylene is first dissolved in xylene at a concentration of 200 g / l or less, and then polypropylene is further added and dissolved. The method of modifying a polyolefin ". The present invention will be described in detail below.

When the Weissenberg effect at the time of dissolution was examined by changing the amount ratio of the solvent and the polyolefin, it was found that the Weissenberg effect does not substantially occur below a certain concentration. For example, xylene is used as a solvent, polypropylene (MI = 0.5) is used as a polyolefin,
When dissolved at 140 ° C., which is the boiling point of xylene, the Weissenberg effect does not occur if polypropylene is 20 g or less per 100 ml of solvent. On the other hand, as described above, the Weissenberg effect due to the increase in viscosity is a temporary phenomenon that occurs in the process of dissolving the polyolefin in the organic solvent. Therefore, when dissolving more than 20 g of polypropylene in 100 ml of xylene, polypropylene is added to the solvent at a low concentration so that the Weissenberg effect does not occur, and after completely dissolving, polypropylene is again added and dissolved. Was repeated, it was found that the Weissenberg effect due to the increase in viscosity did not occur.

The number of divisions is not particularly limited as long as the Weissenberg effect does not occur, but the larger the number, the more preferable, and the more effective the increase in viscosity is by dissolving at least three times. Can be suppressed. The amount of one addition is usually 18 g or less, preferably 12 g, and more preferably 10 g or less with respect to 100 ml of the solvent, although it varies depending on the amounts of the polyolefin and the solvent. In the present invention, the polyolefin is divided and added several times, and the addition amount of each time may be equal, and the amount may be changed within a range in which the Weissenberg effect is not produced. The temperature of the solvent during dissolution may be any value as long as it is a temperature at which the polyolefin is dissolved, but when industrially carried out,
It is preferable that the temperature close to the boiling point of the solvent is easily controlled. The method of the present invention is an effective method for preventing a rapid increase in viscosity when a polyolefin is dissolved. Therefore, even when the Weissenberg effect does not occur, it is preferably applied when it is desired to avoid a rapid increase in viscosity.

The polyolefin used in the present invention includes polypropylene, polyethylene, ethylene-α-olefin copolymer; polybutadiene, ethylene-propylene copolymer rubber, ethylene-propylene-diene copolymer rubber, ethylene-butene-1. Olefin rubber such as copolymer rubber, ethylene-vinyl ester copolymer such as ethylene-vinyl acetate copolymer; ethylene such as ethylene-alkyl acrylate copolymer, ethylene-methacrylic acid alkyl ester copolymer One or a mixture of a copolymer with an α, β-carboxylic acid or a derivative thereof; a propylene-based polymer such as polypropylene or a propylene-ethylene copolymer; a polybutene-based polymer or the like is used.

Examples of the ethylene-vinyl ester copolymer include ethylene and vinyl propionate, vinyl acetate, vinyl caproate, which are produced by a high pressure radical polymerization method.
Examples thereof include copolymers with vinyl ester monomers such as vinyl caprylate, vinyl laurate, vinyl stearate and vinyl trifluoroacetate. Also, ethylene and α, β
-As the copolymer with an unsaturated carboxylic acid or a derivative thereof, an ethylene-α, β-unsaturated carboxylic acid copolymer,
In addition to the ethylene-α, β-unsaturated carboxylic acid ester copolymer, amides, imides and the like thereof can be mentioned. Specific examples of these copolymers include ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-
Ethyl acrylate copolymer, ethylene-acrylic acid-ethyl acrylate copolymer, ethylene-vinyl acetate-ethyl acrylate copolymer, ethylene-glycidyl methacrylate copolymer, ethylene-glycidyl methacrylate-ethyl acrylate copolymer Examples thereof include polymers.

When a monomer having a functional group is used for modification, a polyolefin having a tertiary carbon atom such as polypropylene undergoes severe cleavage without solvent and is difficult to modify. It is necessary to do. Therefore, the method of the present invention is particularly effective when modifying polypropylene.

In the present invention, a usual method is used to carry out the modification. For example, a monomer having a functional group is added to a solvent, the polyolefin is divided as described above while the temperature is raised, and the predetermined amount is completely dissolved in the solvent and then 1
The catalyst is added at 30 ° C. or higher, and the mixture is further stirred at 130 to 140 ° C. for 3 hours to complete the reaction. For recovering the modified polyolefin, various ordinary methods such as precipitation by adding a poor solvent and distilling off unreacted components by distillation are used.

The solvent used in the present invention is not particularly limited as long as it is a good solvent, but it must be one that does not react with a reaction initiator or a monomer having a functional group. For example, one or a mixture of alkylbenzenes such as toluene and xylene, cycloparaffins, decalins, tetrahydrofuran (THF), halogenated aromatic compounds such as chlorobenzene, and the like are used.

Examples of the monomer having a functional group of the present invention include a carboxylic acid group, a carboxylic acid ester group or an acid anhydride group-containing monomer, an epoxy-containing monomer, a hydroxyl group-containing monomer, an amine-containing monomer, an alkenyl cyclic iminoether derivative, and a polyfunctional compound. One or a mixture of a monomer, an organic titanate compound and an unsaturated organic silane compound may be used. These monomers preferably have a double bond.

Examples of the above carboxylic acid group, carboxylic acid ester group or acid anhydride group-containing monomer include α, β-, such as maleic acid, fumaric acid, citraconic acid and itaconic acid.
Unsaturated dicarboxylic acids; Unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, furanic acid, crotonic acid, vinylacetic acid, pentenoic acid; etc. Esters or anhydrides of these α, β-unsaturated dicarboxylic acids or unsaturated monocarboxylic acids Is mentioned.

Examples of the epoxy-containing monomer include glycidyl acrylate, glycidyl methacrylate, itaconic acid monoglycidyl ester, butenetricarboxylic acid monoglycidyl ester, butenetricarboxylic acid diglycidyl ester, butenetricarboxylic acid triglycidyl ester; α-chloroallyl, malein. Glycidyl esters such as acids, crotonic acid and fumaric acid; vinyl glycidyl ether, allyl glycidyl ether, glycidyl oxyethyl vinyl ether, glycidyl ethers such as styrene-p-glycidyl ether; p-glycidyl styrene and the like are particularly preferable. Examples thereof include glycidyl methacrylate and allyl glycidyl ether.

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.

Examples of the amine-containing monomer include tertiary amine-containing monomers such as dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, dibutylaminoethyl acrylate and dibutylaminoethyl methacrylate.

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

[0019]

[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 denaturing 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.

As the polyfunctional monomer, polyfunctional methacrylate monomers represented by trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, etc .; divinylbenzene, triallyl isocyanurate, diallyl phthalate, vinyl butyrate, etc. Examples of polyfunctional vinyl monomers; N, N'-m-phenylene bismaleimide, bismaleimides represented by N, N'-ethylene bismaleimide; and dioximes such as p-quinone dioxime. Be done.

As the organic titanate compound, tetra
(2,2-diallyloxymethyl-1-butyl) .bis (di-tridecyl) phosphite titanate, isopropyl dimethacryl isostearoyl titanate, isopropyl isostearoyl diacryl titanate, tetraisopropyl titanate, tetra- Examples thereof include n-butyl titanate, tetrakis (2-ethylhexoxy) titanate, and titanium lactate ammonium salt.

Examples of unsaturated organic silane compounds include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetylsilane and vinyltrichlorosilane.

Among various monomers having the above-mentioned functional groups, maleic anhydride is most preferable because of its excellent performance of modified products, high reactivity, economical and easy availability. used. The amount of monomer used is
50 to 300 parts by weight is preferable with respect to 100 parts by weight of polyolefin. If the amount of the monomer used is less than 50 parts by weight, the effect of the invention cannot be obtained because the amount added to the polyolefin is too small, and if it exceeds 300 parts by weight, the monomers polymerize with each other to produce a heavy by-product. Is also not preferable. The above-mentioned monomer may be introduced into the reaction system either before, at the same time as, or after the polyolefin is dissolved.

The catalyst used in the modification of the present invention is generally a method using a radical generator such as an organic peroxide as a reaction initiator, but is not particularly limited. Examples of the radical generator include benzoyl peroxide, lauryl peroxide, dicumyl peroxide, t
ert-Butyl hydroperoxide, α, α-bis (tert-
Butyl peroxydiisopropyl) benzene, di-tert
In addition to organic peroxides such as -butyl peroxide and 2,5-di (tert-butylperoxy) hexine, azobisisobutyronitrile, 2,3-dimethyl-2,3-diphenylbutane, 2,3- 1 type selected from diethyl-2,3-diphenylbutane, 2,3-diethyl-2,3-di (p-methylphenyl) butane, 2,3-diethyl-2,3-di (bromophenyl) butane or Mixtures of these are used.

The amount of the radical generator used is 1 to 15 parts by weight, preferably 3 parts by weight, based on 100 parts by weight of the polyolefin.
It is in the range of 10 to 10 parts by weight. If it is less than 1 part by weight, the effect of generating radicals is not sufficiently exerted and the effect of modification is small. If it is used in excess of 15 parts by weight, the cleavage or crosslinking reaction of the polyolefin itself occurs excessively, which is not preferable.

<Measurement of concentration at which the Weissenberg effect occurs> In a 1-liter round bottom flask, xylene (special grade reagent,
300 ml of Kishida Chemical Co., Ltd., same as below and polypropylene (trade name: E110P, Nippon Petrochemical Co., Ltd., same below) in the amount shown in Table 1 are put into the mantle heater while heating the motor (max. Torque 2kg ・ cm,
Product Name: Three One Motor TYPE-600G, Shinto Kagaku
(Manufactured by Co., Ltd., the same applies hereinafter) was stirred at 80 rpm using a stirrer equipped with a screw blade having a total length of 50 mm,
The presence or absence of the Weissenberg effect shown in FIG.
The results are shown in Table 1. Polypropylene concentration is 300 solvent
At 60 g (200 g / l) or less per ml, the Weissenberg effect was not observed.

[0028]

[Table 1]

[0029]

EXAMPLES Examples will be shown below, but the present invention is not limited to the examples. Example 1 Xylene 50 in a 1 liter round bottom flask.
0 ml and maleic anhydride (special grade reagent, Kishida Chemical
74 g (manufactured by Co., Ltd., the same applies hereinafter) was added and the atmosphere was sufficiently replaced with nitrogen. Next, it was heated with a mantle heater while stirring at 300 rpm using a motor. Liquid temperature is 130-14
When the temperature reached 0 ° C., 40 g of polypropylene was added, and after completely dissolving this, 40 g of polypropylene was again added to the reaction system and dissolved, but the increase in viscosity was not so large. Thereafter, when 40 g of polypropylene was further added to the reaction system, the liquid viscosity temporarily increased, but soon decreased. Although a total of 120 g of polypropylene was dissolved, the increase in viscosity was relatively small, the phenomenon that polypropylene was not entangled with the stirrer due to the Weissenberg effect was hardly seen, and the reaction proceeded smoothly. Next, increase the liquid temperature to 140 ° C.
While maintaining the above, 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 1 hour. 2 hours after dropping, the liquid temperature is 140
The reaction was completed by keeping the temperature at 0 ° C. The maleated polypropylene obtained had a maleation rate of 2.2%, and a high addition rate was achieved. The conditions and reaction state are shown in Table 2.

<Example 2> The amount of polypropylene added was 1
The same procedure as in Example 1 was carried out except that the amount was 24 g per batch and the addition was performed in 5 batches. The increase in liquid viscosity was smaller than that in Example 1, the Weissenberg effect was not observed, and the reaction proceeded smoothly. The maleated polypropylene obtained had a high maleation ratio of 2.2% as in Example 1. The conditions and reaction state are shown in Table 2.

Example 3 Example 3 was repeated except that maleic anhydride was added after the polypropylene was dissolved. No Weissenberg effect was observed and the reaction proceeded smoothly. The maleated polypropylene obtained had a high maleation ratio of 2.2% as in Example 1. The conditions and reaction state are shown in Table 2.

<Comparative Example 1> The procedure of Example 1 was repeated except that 120 g of polypropylene was added all at once. The Weissenberg effect was generated, and the whole liquid became entangled with the stirring rod, making stirring difficult. Furthermore, the load on the stirring device increased, the motor tripped, stirring stopped, and it became impossible to continue the reaction. The conditions and reaction state are shown in Table 2.

<Comparative Example 2> The procedure of Example 1 was repeated, except that polypropylene and a solvent were placed in a flask in advance and the temperature was raised. Comparative Example 1 at 115 ° C. during heating
As in the case of No. 1, the Weissenberg effect occurred, stirring was stopped, and it became impossible to continue the reaction. The conditions and reaction state are shown in Table 2.

[0034]

[Table 2]

[0035]

By using the method of the present invention, it has become possible to avoid the Weissenberg effect due to a rapid increase in viscosity which has been a problem in the past when a polyolefin is dissolved in an organic solvent. Therefore, when industrially implemented, it does not require a special device such as a heat source temperature control device,
It can be dissolved efficiently in a short time. This allows
Even when the polyolefin is dissolved in a solvent and then modified with a monomer having a functional group, it can be efficiently carried out.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a mode of occurrence of the Weissenberg effect.

[Explanation of symbols]

 1 Round bottom flask 2 Stirring blade 3 Liquid level 4 Stirring shaft

Claims (3)

[Claims] 1. When modifying a polyolefin with a monomer having a functional group in the presence of a good solvent, by dividing the polyolefin and adding it to the solvent, the Weisenberg effect can be completely eliminated without substantially causing it. Dissolve
A method for modifying a polyolefin, which comprises performing a modification thereafter. 2. When the polyolefin is divided and added to the solvent, the polyolefin is dissolved in the solvent at a concentration lower than the concentration at which the Weissenberg effect is substantially generated, and then the polyolefin is further added to increase the concentration of the polyolefin. The method according to claim 1, characterized in that
The method for modifying a polyolefin according to 1. 3. The solvent and the polyolefin are xylene and polypropylene, respectively, and polypropylene is first dissolved in xylene at a concentration of 200 g / l or less, and then polypropylene is further added and dissolved. Or the method for modifying a polyolefin according to 2.