JPH0987474A - Production of silane-modified polyolefin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To readily produce a silane-modified polyolefin having high gel frac tion, excellent in a variety of properties and in resistance to oxidative deteriora tion through one step process where an antioxidant can be stably added in the silane-modification of polyolefin using an extruder. SOLUTION: (A) A polyolefin, (B) a vinyl silane and (C) a liquid composition containing (i) an amine antioxidant and (ii) a radical polymerization initiator are mixed in an extruder under heating to effect the grafting reaction. As the component A, a low-density polyethylene, high-density polyethylene and the like are cited, while vinyltrimethoxysilane and, vinyltriethoxysilane are preferred as the component B. The amount of the component B is 0.5-10 pts.wt., preferably 0.7-5 pts.wt. per 100 pts.wt. of the component A. The component C is preferably 2,6-dimethylpiperidine or a naphthylamine compound and the component D is preferably dicumyl peroxide.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a silane-modified polyolefin.

[0002]

2. Description of the Related Art Silane-modified polyolefin undergoes a cross-linking reaction when it comes into contact with water, and has various properties such as mechanical strength, heat resistance, creep resistance, environmental stress crack resistance, chemical resistance, etc. Since it is significantly improved in comparison, it is preferably used as a raw material for covered electric wires, hot water supply pipes, flame-retardant materials and the like.

Conventionally, as a method for molding the above-mentioned silane-modified polyolefin by utilizing a water-crosslinking reaction, there is a two-step method in which a grafting step of silane-modifying the polyolefin and a molding step of shaping it into a desired shape are divided. It is common.

However, in the case of the above-mentioned two-step method, a step of extruding and granulating the silane-modified polyolefin obtained through the grafting step in advance is required, which complicates the process and complicates the work. When the granules absorb moisture, the water-crosslinking reaction proceeds to lower the fluidity, so that there is a problem that the shapeability in the molding step, which is a subsequent step, is significantly deteriorated.

On the other hand, the one-step method in which the grafting step and the molding step are continuously carried out by a series of extruders is an excellent method which is simple and has excellent workability and is hardly affected by moisture. There is a problem that it is difficult to add trace components such as a polymerization catalyst for the modified polyolefin, an antioxidant and a colorant during the process.

That is, in the case of the two-step method, it is easy to granulate the above-mentioned trace components in advance to prepare a masterbatch, and this masterbatch can be easily mixed in the molding step. There is a problem that it is necessary to introduce auxiliary equipment such as an auxiliary extruder in order to appropriately add

On the other hand, since the antioxidant is also a radical scavenger in many cases, there is a concern that the graft reaction may be hindered. Therefore, it is preferable to add the antioxidant into the extruder after the graft reaction is completed.

As an example of a method for molding a silane-modified polyolefin by a one-step method, Japanese Patent Publication No. 60-6045 discloses that either a mixed solution of a silanol condensation catalyst and a free radical generator, or an unsaturated silane which can be hydrolyzed. One is supplied into the screw type extruder together with the polyolefin from the hopper, and the other is pressed into the extruder through the liquid injection hole provided in the cylinder or screw, then kneaded, and then extruded to coat the extrudate on the conductor. A method for producing a cross-linked polyolefin is proposed which is characterized by contacting with water and then cross-linking.

However, the method according to the above proposal is suitable for supplying either the liquid mixture of the silanol condensation catalyst and the free radical generator or the liquid unsaturated silane into the extruder in the middle of the extruder. However, it is difficult to add a small amount of the antioxidant, which is generally a powder, into the extruder in the middle of the extruder, and the above-mentioned problems cannot be completely solved.

[0010]

In order to solve the above-mentioned problems of the prior art, the present invention stably prevents oxidation in the silane modification step of a polyolefin using an extruder without affecting the graft reaction. An object of the present invention is to provide a method for producing a silane-modified polyolefin by a one-step method to which an agent can be added.

A method for producing a silane-modified polyolefin according to the present invention comprises a polyolefin, and
A liquid composition prepared by dissolving an amine-based antioxidant and a radical polymerization initiator in a vinylsilane compound is heated and mixed in an extruder to cause a graft reaction, thereby achieving the above object.

The polyolefin used in the method for producing a silane-modified polyolefin according to the present invention is a (co) polymer of an olefinic monomer and is not particularly limited, and examples thereof include low density polyethylene, high density polyethylene, Polyethylene such as linear low-density polyethylene, polypropylene, ethylene-propylene copolymer,
Examples thereof include an ethylene-propylene-diene terpolymer, an ethylene-butene copolymer, an ethylene-vinyl acetate copolymer, an ethylene-acrylic acid ester copolymer, and a chlorinated polyethylene. One or two kinds of them are listed. The above are preferably used, but among them, one kind or two or more kinds of polyethylene such as low density polyethylene, high density polyethylene, linear low density polyethylene and polypropylene, and polypropylene are more preferably used. The "(co) polymer" referred to here
Means a "polymer" or a "copolymer".

The vinylsilane compound used in the method for producing a silane-modified polyolefin according to the present invention is not particularly limited as long as it is a silane compound having a vinyl group, and for example, a compound represented by the following general formula (1) 1 type or 2 types or more of these are used suitably. RR ¹ _n SiY _(3-n) formula (1)

In the above general formula (1), the group R represents a monovalent vinyl hydrocarbon group or a monovalent vinyl hydrocarbonoxy group, and is not particularly limited, but for example,
Vinyl group, allyl group, isopropenyl group, butenyl group,
Cyclohexenyl group, cyclopentadienyl group, γ-
A (meth) acryloxypropyl group and the like can be mentioned, which are preferably used.

Further, in the general formula (1), the group R ¹ represents a hydrogen group or an aliphatic saturated hydrocarbon group such as a methyl group, an ethyl group, a propyl group and a decyl group.

Further, in the above general formula (1), the group Y represents an organic group capable of being hydrolyzed, and is not particularly limited, and examples thereof include a methoxy group, an ethoxy group, a formyloxy group, an acetoxy group, and propionyl. Examples thereof include an oxy group, an alkylamino group and an arylamino group, and one or more of these are preferably used.

Furthermore, in the general formula (1), n represents 0 or 1.

Specific examples of the vinylsilane compound represented by the above general formula (1) include, but are not limited to, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, and the like. One type or two or more types are preferably used.

In the method for producing a silane-modified polyolefin according to the present invention, the amount of the vinylsilane compound used is not particularly limited, but 0.5 to 1 vinylsilane compound is used per 100 parts by weight of the polyolefin.
It is preferably 0 part by weight, and more preferably 0.7 to 5 parts by weight.

When the amount of the vinylsilane compound used is less than 0.5 parts by weight based on 100 parts by weight of the polyolefin,
Since the finally obtained water-crosslinked polyolefin does not have a sufficiently high gel fraction, various properties such as mechanical strength, heat resistance and creep resistance are not sufficiently improved. On the contrary, when it exceeds 10 parts by weight, the silane obtained is Since the melt viscosity of the modified polyolefin becomes too high, the extruder is overloaded and the workability is deteriorated, and the elongation rate and the heat fusion property are deteriorated.

The amine-based antioxidant used in the method for producing a silane-modified polyolefin according to the present invention is not particularly limited, but it is 2,6-dimethylpiperidine-based compound, naphthylamine-based compound, diphenylamine-based compound, p -Phenylenediamine-based compounds and the like can be mentioned, and one kind or two or more kinds thereof are preferably used.

Specific examples of the 2,6-dimethylpiperidine compound are not particularly limited, but bis (2,2,6,6-tetramethyl-4-piperidyl)
Low molecular weight hindered amine compounds such as sebacate and bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and poly [{6- (1,1,3,3-tetramethylbutyl) amino- 1,3,5-triazine-
2,4-diyl {(2,2,6,6-tetramethyl-
4-piperidyl) imino {hexamethylene} (2,2
6,6-4-Tetramethyl-4-piperidyl) imino}], dimethyl succinate.1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, etc. Examples thereof include high molecular weight hindered amine compounds, and one or more of these are preferably used.

Specific examples of the naphthylamine compounds are not particularly limited, but include phenylnaphthylamine, aldolnaphthylamine and the like, and one or more of these are preferably used.

Further, specific examples of the diphenylamine compound are not particularly limited, but p-
Isopropyloxydiphenylamine, (p-toluenesulfonylamide) -diphenylamine, N, N′-diphenylethylenediamine and the like can be mentioned.
Species or two or more species are suitably used.

Further, specific examples of the p-phenylenediamine compound include N, N'-diphenyl-p-
Phenylenediamine, N, N'-di- (2-naphthyl)
-P-phenylenediamine, N, N'-bis (1-methylheptyl) -p-phenylenediamine, N, N'-bis (1,4-dimethylpentyl) -p-phenylenediamine and the like can be mentioned. One type or two or more types are preferably used.

Among the various amine-based antioxidants mentioned above,
Generally, one or more of 2,6-dimethylpiperidine compounds, which have little influence on the graft reaction, are more preferably used, and when the silane-modified polyolefin is used for applications such as a water-crosslinking pipe for hot water. Include the above poly [{6- (1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl}.
{(2,2,6,6-tetramethyl-4-piperidyl)
One or more high molecular weight hindered amine compounds such as imino} hexamethylene {(2,2,6,6-4-tetramethyl-4-piperidyl) imino}] are particularly preferably used.

In the method for producing a silane-modified polyolefin according to the present invention, the amount of the amine-based antioxidant used is not particularly limited. 05
It is preferably from 1 to 1 part by weight, and particularly from 0.1 to 1.
It is more preferably 0.5 part by weight.

If the amount of the amine-based antioxidant used is less than 0.05 parts by weight based on 100 parts by weight of the polyolefin, the antioxidant effect of the finally obtained water-crosslinked polyolefin cannot be sufficiently obtained, so that the machine for a long period of time cannot be used. Characteristics such as dynamic strength, creep resistance, and weather resistance are insufficient,
On the other hand, if the amount exceeds 1 part by weight, it is not preferable because it may cause the coloring (yellowing) of the silane-modified polyolefin and increase the cost although it is no longer expected to improve various properties.

The radical polymerization initiator used in the method for producing a silane-modified polyolefin according to the present invention may be any compound generally used in the graft reaction of polyolefin, and is not particularly limited, but for example, , Benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, t-butylperoxyacetate, t-butylperoxybenzoate, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) ) Organic peroxides such as hexane, di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3, azobisisobutyronitrile and dimethylazodiisobutene. Examples include azo compounds such as tylate, and one or more of these are preferably used. Among them, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, di-t-butylperoxide, 2,5-dimethyl-2,5-di ( One or more of t-butylperoxy) hexyne-3 and the like are more preferably used.

In the method for producing a silane-modified polyolefin according to the present invention, the amount of the radical polymerization initiator used is not particularly limited, but 0.01 radical polymerization initiator is added to 100 parts by weight of the above-mentioned polyolefin.
Is preferably 5 to 5 parts by weight, and more preferably 0.02 to
It is more preferably 2 parts by weight.

If the amount of the radical polymerization initiator used is less than 0.01 parts by weight based on 100 parts by weight of the polyolefin, the desired gel fraction cannot be obtained because the graft reaction does not proceed sufficiently, and conversely exceeds 5 parts by weight. In addition, since the number of free radical sites in the polyolefin becomes too large and so-called peroxide cross-linking proceeds, scorch phenomenon (premature cross-linking phenomenon) occurs, surface smoothness decreases, viscosity abnormally increases, etc. Is reduced.

In the method for producing a silane-modified polyolefin according to the present invention, the above-mentioned essential components of the polyolefin, the vinylsilane compound, the amine-based antioxidant and the radical polymerization initiator may be used together with the above-mentioned essential components, if necessary, within a range that does not impair the object of the present invention. One or more of various additives such as silanol condensation catalyst, ultraviolet absorber, process heat stabilizer, organic or inorganic filler, pigment, dye and processing aid may be used in combination.

Among the various additives described above, the combined use of the silanol condensation catalyst is effective because it can improve the efficiency in the water crosslinking step.

The silanol condensation catalyst is not particularly limited as long as it is any compound generally used as a catalyst for promoting dehydration condensation between silane and silanol, and examples thereof include dibutyltin dilaurate and
Dibutyltin diacetate, dibutyltin dioctoate,
Compounds such as stannous acetate, cobalt naphthenate, lead naphthenate, ethylamine, dibutylamine, hexylamine and pyridine, inorganic acids such as sulfuric acid and hydrochloric acid, organic acids such as toluenesulfonic acid, acetic acid, stearic acid and maleic acid And one or more of these are preferably used, and among them, dibutyltin dilaurate is more preferably used.

The amount of the silanol condensation catalyst used is not particularly limited, but the above-mentioned polyolefin 10 is used.
The silanol condensation catalyst is preferably 0.001 to 5 parts by weight, more preferably 0.005 to 1 part by weight, based on 0 parts by weight.

When the amount of the silanol condensation catalyst used is less than 0.001 part by weight based on 100 parts by weight of the polyolefin, the catalyst function is not sufficiently exhibited, so that the water crosslinking step requires a long time, and conversely, it exceeds 5 parts by weight. Then, premature cross-linking occurs in the extruder and a scorch phenomenon occurs.

The ultraviolet absorber is not particularly limited, but it is 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- {2-hydroxy-3,5-bis (α). , Α-Dimethylbenzyl) phenyl} -2H-benzotriazole, 2- (3-t-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5-di-t- Examples thereof include benzotriazole-based compounds such as butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, and one or more of these are preferably used.

In the method for producing a silane-modified polyolefin according to the present invention, a polyolefin and a liquid composition obtained by dissolving an amine antioxidant and a radical polymerization initiator in a vinylsilane compound are heated and mixed in an extruder to cause a graft reaction. It is necessary.

The method for preparing the above liquid composition is not special, and for example, using a normal stirring mixer, at room temperature or under heating, in a predetermined amount of a vinylsilane compound, a predetermined amount of an amine antioxidant. Further, the radical polymerization initiator may be added, and the mixture may be stirred and mixed to be dissolved to form a uniform liquid composition.

In the process of preparing the above liquid composition, the method of dissolving the amine-based antioxidant and the radical polymerization initiator in the vinylsilane compound is not particularly limited, but unnecessary decomposition of the radical polymerization initiator may be performed. In order to prevent it, it is preferable to first dissolve the amine-based antioxidant in the vinylsilane compound and then add and dissolve the radical polymerization initiator. Further, in the case of performing the dissolution under heating, the radical polymerization initiator It is preferable to perform sufficient temperature control so that decomposition does not occur.

The method of introducing the polyolefin and the liquid composition obtained above into the extruder is not particularly limited as long as it can be carried out by an ordinary method, but the polyolefin is the resin feed part of the extruder. More, the liquid composition, for example, by using a liquid transport pump, in the vicinity of the resin feed portion of the extruder, or in the extruder downstream of the portion where the polyolefin melts by heat Is preferred.

The extruder used in the method for producing the silane-modified polyolefin according to the present invention is not particularly limited and may be an extruder generally used in general.
A single-screw extruder, a twin-screw extruder, a multi-screw extruder having three or more screws, and the like can be mentioned, and any of them is preferably used.

The above single-screw extruder is not particularly limited, but is not limited to an extruder having a general full flight type screw, but also an extrusion having a discontinuous flight type screw, a pin barrel, a mixing head and the like. A machine and the like are also included, and any of them is preferably used.

Further, as the above twin-screw extruder,
Although not particularly limited, a meshing same-direction rotary extruder, a meshing different-direction rotary extruder, a non-meshing different-direction rotary extruder, and the like are mentioned, and any of them is preferably used.

Among the various screw type extruders mentioned above,
Considering the kneading performance and the like, a meshing (self-wiping) co-rotating twin-screw extruder is more preferably used.

The shape of the screw of the extruder is not particularly limited, but it is partially a kneading disk, a seal ring, a reverse screw, and a rotor, centering on a 2-3 flight type full flight type. Those having a screw element such as are preferably used.

Further, in the method for producing a silane-modified polyolefin according to the present invention, a die having a desired shape is installed at the tip of the extruder, and the obtained silane-modified polyolefin is shaped into a desired shape by a one-step method. The process may be simplified by continuously performing the graft reaction and the molding.

The operating conditions of the extruder in the method for producing a silane-modified polyolefin according to the present invention are not particularly limited. For example, the screw rotation speed, the extrusion amount, the set temperature of the cylinder, the residence time in the extruder, the kneading degree, etc. It may be appropriately determined in consideration of the parison strength at the time of molding, etc. Further, in order to remove unnecessary substances such as residual water, residual vinylsilane compound, radical polymerization initiator residue, and the like, for example,
A vacuum vent may be provided in the latter stage of the extruder.

The method for molding the silane-modified polyolefin obtained by the method for producing a silane-modified polyolefin according to the present invention is not particularly limited, and a die having a desired shape is installed at the tip of an extruder to obtain the silane-modified polyolefin obtained. By shaping the polyolefin into a desired shape, the graft reaction and molding may of course be carried out continuously by a one-step method,
Alternatively, the obtained silane-modified polyolefin may be once granulated and then subjected to a two-step method of shaping the silane-modified polyolefin into a desired shape by an extruder. Further, the obtained silane-modified polyolefin is once granulated and then blown. It may be performed by a method other than extrusion molding such as molding, calender molding, and injection molding, in which a desired shape is obtained.

Among the various molding methods described above, a so-called one-step molding method in which a die having a desired shape is installed at the tip of an extruder and the obtained silane-modified polyolefin is shaped into a desired shape is extremely effective.

That is, in the molding method by the one-step method,
By taking a method in which an amine-based antioxidant has already been introduced into the polyolefin together with the vinylsilane compound which is a monomer of the graft reaction, and an additive such as a silanol condensation catalyst is directly added to the system from the latter part of the extruder. However, there is an advantage that the step of preparing in advance a masterbatch containing an additive such as an antioxidant and a silanol condensation catalyst, which is required in a usual two-step method, is unnecessary.

In any of the above-mentioned molding methods, the shaped silane-modified polyolefin is water-crosslinked by bringing it into contact with water to form a final desired molded body.
The method of water-crosslinking is not particularly limited, but includes a high-temperature hot-water treatment method, an underwater immersion method, and the like, and any of them is preferably adopted.

(Function) According to the production method of the present invention, since a liquid composition obtained by previously dissolving a trace amount of an amine-based antioxidant and a radical polymerization initiator in a vinylsilane compound is used, these trace components can be stably added. It can be fed into the extruder and the process is simple.

Further, conventionally, in the above-mentioned production method, it has been considered that the amine-based antioxidant acts as a radical scavenger and inhibits the graft reaction. However, when the production method of the present invention is actually adopted, It was found that the grafting reaction was not hindered and surprisingly the grafting reaction was rather accelerated. The reason for this is not clear, but it is considered that the amine-based antioxidant functions as a decomposition accelerator of the radical polymerization initiator and the decomposition efficiency of the radical polymerization initiator is improved.

[0054]

BEST MODE FOR CARRYING OUT THE INVENTION In order to explain the present invention in more detail, examples will be given below. In the examples, “parts” means “parts by weight”.

(Example 1)

( 1) Preparation of Liquid Composition As shown in Table 1, vinyltrimethoxysilane (trade name “Sila Ace S210”, as a vinylsilane compound,
(Manufactured by Chisso Co.) 1 part, poly [{6- (1,
1,3,3-tetramethylbutyl) amino-1,3,5
-Triazine-2,4-diyl} {2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-4-tetramethyl-4-piperidyl) imino} ] (Product name "CHIMASSORB 944
LD ", manufactured by Ciba-Geigy) and 2,5-dimethyl-2,5-di (t-butylperoxy) hexane (trade name" Perhexa 25 "as a radical polymerization initiator.
B ", manufactured by Nippon Oil & Fats Co., Ltd.) was put into a tank at a ratio of 0.08 part and uniformly mixed by stirring to prepare a liquid composition.

( 2) Silane-modified polyolefin and molding
Body production Self-wiping type twin screw element and screw (diameter 47 mm, L / D = 35) composed of kneading disc element and meshing type co-rotating twin screw extruder equipped with 10-division cylinder barrel A molding die for pipe having an inner diameter of 21.5 mm and an outer diameter of 16.2 mm was connected to the tip of (model "TEX-44 type", manufactured by Japan Steel Works, Ltd.). In addition, the installation of the 10-divided cylinder barrel is from the first barrel to the tenth barrel from the upstream side to the downstream side of the extruder, and the temperature of each barrel and the pipe forming die is from the first barrel to the tenth barrel. 6 barrels to 17
The temperature was set to 0 ° C, the seventh barrel was set to 155 ° C, the eighth barrel to the tenth barrel, and the pipe forming die were set to 140 ° C.

Linear low-density polyethylene (trade name "Rinirex AR4810", manufactured by Nippon Petrochemical Co., Ltd.) was charged into the hopper, and 20 k using a screw feeder.
The extruder was fed through the feed port at a feeding rate of g / hour.
At the same time, a micro pump (model “VC-102 MOD
EL186-346 ", manufactured by Chuo Science Co., Ltd.), the liquid composition obtained above was supplied to the extruder through the same supply port at a supply rate of 266 g / hour. Further, dibutyltin dilaurate as a silanol condensation catalyst was fed by a plunger pump at a feed rate of 8 g / hour, and was fed from a ninth barrel to an extruder through a press-fitting nozzle. During this period, the extruder was operated at a screw rotation speed of 40 rpm and discharged from the pipe forming die discharge port to obtain a pipe-shaped shaped product of silane-modified polyethylene. Then, using a curing device, the obtained pipe-shaped shaped body was aged under steam at 110 ° C. for 4 hours to be water-crosslinked to prepare a silane-modified polyolefin pipe-shaped molded body.

( 3) Evaluation The gel fraction, the hot internal pressure creep performance (1 hour creep), and the hot internal pressure creep performance (8000 hour creep) of the pipe-shaped molded product of the silane-modified polyethylene obtained above were measured by JIS. It evaluated based on K-6769 "crosslinked polyethylene pipe." The results were as shown in Table 1.

(Example 2)

As shown in Table 1, in the preparation of the liquid composition, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate (commercial product) which is a low molecular weight hindered amine compound as an amine antioxidant is used. Name "TINUV
IN770DF ", manufactured by Ciba-Geigy Co., Ltd.) was used to prepare a silane-modified polyolefin and a pipe-shaped molded product of the silane-modified polyolefin in the same manner as in Example 1.

(Comparative Example 1)

As shown in Table 1, a silane-modified polyolefin and a pipe-shaped molded product of the silane-modified polyolefin were produced in the same manner as in Example 1 except that an antioxidant was not used in the preparation of the liquid composition. .

(Comparative Example 2)

As shown in Table 1, in the preparation of the liquid composition, pentaerythrityl-tetrakis {3- (3,5) which is a hindered phenol compound as a phenolic antioxidant is used instead of the amine antioxidant. -Di-t-
Butyl-4-hydroxyphenyl) propionate}
A silane-modified polyolefin and a pipe-shaped molded product of the silane-modified polyolefin were produced in the same manner as in Example 1 except that (trade name "IRGANOX1010", manufactured by Ciba Geigy) was used.

(Comparative Example 3)

A liquid composition was prepared by adding 1 part of vinyltrimethoxysilane "Sila Ace S210" as a vinylsilane compound and 0.08 part of a radical polymerization initiator "Perhexa 25B" to a tank and uniformly stirring and mixing. On the other hand, using a tumbler (model "MT-50", manufactured by Matsui Seisakusho), stir for 10 minutes at a ratio of 100 parts of linear low-density polyethylene "LINEREX AR4810" and 0.25 part of amine antioxidant "CHIMASSORB 944LD". A polyethylene composition containing an amine antioxidant was prepared by mixing. Then, using the same extruder as in Example 1, the polyethylene composition containing the amine-based antioxidant obtained above was charged into the hopper,
A screw feeder was used to supply the extruder at a supply rate of 20.05 kg / hour from the supply port. At the same time, using the same micropump as in Example 1, the liquid composition obtained above was supplied to the extruder through the same supply port at a supply rate of 216 g / hour. Hereinafter, in the same manner as in Example 1, a silane-modified polyolefin and a pipe-shaped molded product of the silane-modified polyolefin were produced.

Gel fraction, hot internal pressure creep performance (1 hour creep), and hot internal pressure creep performance (of the silane-modified polyolefin pipe-shaped molded products obtained in Example 2 and Comparative Examples 1 to 3) 8000 hour creep)
The results of evaluation in the same manner as in Example 1 are as shown in Table 1.

[0069]

[Table 1]

[0070]

As described above, according to the production method of the present invention, it is possible to stably and easily obtain a silane-modified polyolefin which has a high gel fraction and is excellent in various properties and is also excellent in resistance to oxidative deterioration. .

Claims (1)

[Claims] 1. A method for producing a silane-modified polyolefin, characterized in that a polyolefin and a liquid composition obtained by dissolving an amine-based antioxidant and a radical polymerization initiator in a vinylsilane compound are heated and mixed in an extruder to cause a graft reaction. Method.