JP2003105027A - Melt moldable silane slightly crosslinked olefin based resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a melt moldable silane slightly crosslinked olefin based resin which improves a melt tension without greatly damaging flowability, and particularly excels in moldability, a hollow molded product and a film molded product which are molded from the silane slightly crosslinked olefin based resin and have excellent external appearance. SOLUTION: The silane slightly crosslinked olefin based resin has a gel fraction of <=3 wt.% and the relationship between a high load melt mass flow rate, measured with the use of a load of 21.60 kg, and the melt tension, measured at 190 deg.C which meets formula (1): MS>=550×e<-0.108x(> HLMFR<)> (wherein MS is a melt tension (unit: mN); HLMFR is a high load melt mass flow rate (unit: g/10 min) ; and e is a natural logarithmic base).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silane slightly crosslinked olefin resin having good molding and processing characteristics in molding methods such as blow molding, inflation molding, cast molding and laminate molding. In particular, the present invention relates to a melt-moldable silane finely crosslinked olefin resin having a good surface appearance and stable productivity in hollow molding and inflation molding, in which the resin is required to have a high melt tension.

[0002]

2. Description of the Related Art Among molding methods, particularly in hollow molding and inflation molding, it is necessary to use a resin having a high melt tension in order to perform stable processing. For example, in the case of molding a plastic drum by hollow molding, it is necessary to select a resin having a large melt tension for its molecular weight in order to perform stable molding without sagging or breaking of the parison. Similar characteristics are required to prevent bubble swaying and tearing in inflation molding, or to suppress width reduction in T die molding.

As a method for improving the moldability by improving the melt tension of the resin, an olefin resin is melt-kneaded with a radical initiator such as an organic peroxide to form crosslinks between polymer molecules, Methods for increasing high molecular weight components are known.

As another method, a method of obtaining a crosslinked product by subjecting a silane-modified olefin resin to hot water treatment in the presence of a silanol condensation catalyst, a so-called silane crosslinking method, has hitherto been used in applications such as crosslinked pipes and electric wire clothing. Are known.

[0005]

However, in the method of improving the melt tension by using a radical initiator, the melt tension is not significantly improved due to the formation of crosslinks, but the fluidity of the resin is remarkably lowered. There are problems such as deterioration of moldability and poor appearance due to generation of gel.

The silane cross-linking method is used exclusively for forming a highly gelled resin composition for the purpose of obtaining a molded article having excellent physical strength and electrical characteristics. For example, for cross-linked polyethylene pipe, JIS K
6769 (2000) stipulates that a gel fraction of 65% by weight or more is required. Since such a resin has no fluidity, it cannot be used for blow molding or inflation molding.

No attempt has been made so far to use an olefin resin which has been cross-linked to such an extent that it does not form a gel by the silane cross-linking method, that is, finely cross-linked, for molding such as hollow molding and inflation molding.

The present invention solves the above problems and provides a melt-moldable silane slightly cross-linked olefin resin which improves melt tension without significantly impairing fluidity and is particularly excellent in moldability. is there. Further, the present invention provides a hollow molded article and a film molded article, which are molded from the silane slightly crosslinked olefin resin and have an excellent appearance.

[0009]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a silane finely crosslinked olefin resin having specific characteristics improves melt tension without significantly impairing fluidity. However, they have found that they have excellent moldability, and have completed the present invention.

That is, the present invention has a gel fraction of 3% by weight.
The relationship between the high load melt mass flow rate measured using a load of 21.60 kg and the melt tension measured at 190 ° C. according to JIS K6922-1 (2000) satisfies the following general formula (1). The present invention relates to a melt-moldable silane finely crosslinked olefin-based resin characterized by:

MS ≧ 550 × e ^{−0.108 × (HLMFR)} (1) (where, MS is melt tension (unit: mN), HLMFR
Is a high load melt mass flow rate (unit: g / 10mi
n) and e indicate the base of the natural logarithm. ) And, more preferably, the gel fraction is 3% by weight or less, and JIS K6
The density measured based on 922-1 (2000) is 9
40-965 kg / m ³ , JIS K6922-1 (2
High load melt mass flow rate measured with a load of 21.60 kg based on
The present invention relates to a silane lightly crosslinked olefin resin in which the relationship between the high load melt mass flow rate and the melt tension measured at 190 ° C. in the range of min satisfies the following general formula (2).

MS ≧ 615 × e ^{−0.108 × (HLMFR)} (2) (where, MS is melt tension (unit: mN), HLMFR
Is a high load melt mass flow rate (unit: g / 10mi
n) and e indicate the base of the natural logarithm. ) Hereinafter, the present invention will be described in detail.

The silane slightly cross-linked olefin resin of the present invention has a gel fraction of 3% by weight or less, and JIS K692
2-1 (2000) with a high load melt mass flow rate measured using a load of 21.60 kg and 190
The silane finely crosslinked olefin resin has a relationship of melt tension measured at 0 ° C. that satisfies the general formula (1).

The silane slightly cross-linked olefin resin of the present invention has a fluidity at the time of melting as compared with a conventional uncross-linked olefin resin and a cross-linked olefin resin obtained by cross-linking and modifying an olefin resin with an organic peroxide or the like. Is favorable, the melt tension is high, and the molding processability is good in blow molding and inflation molding.

The silane lightly cross-linked olefin resin of the present invention has a gel fraction of 3% by weight or less because a gel during processing does not cause troubles such as film breakage and a molded product having a good surface can be obtained. . Here, if the gel fraction exceeds 3% by weight, the surface of the molded product obtained when it is subjected to the hollow molding is markedly uneven, and the surface appearance is deteriorated. Further, when a film is formed by inflation molding or the like, there is a problem that unmelted components become foreign matters during the molding process, resulting in poor appearance and deterioration of material strength.

The gel fraction referred to in the present invention means that the sample is 120
After extraction with xylene at 12 ° C for 12 hours, the mixture was filtered through a wire mesh of 200 mesh, the filtration residue was dried at 105 ° C vacuum dryer for 5 hours and weighed, and the ratio of the filtration residue to the sample amount before treatment was expressed as a percentage. It is a thing.

The silane slightly cross-linked olefin resin of the present invention is 2 based on JIS K6922-1 (2000).
The relationship between the high load melt mass flow rate measured using a load of 1.60 kg and the melt tension measured at 190 ° C. satisfies the general formula (1). Here, if the above general formula (1) is not satisfied, there is a problem that stable molding is difficult, such as sagging of the parison in the hollow molding and swaying of bubbles in the inflation molding. Further, in the present invention,
In particular, it is preferable that the above general formula (2) is satisfied because it is a slightly crosslinked olefin resin suitable for hollow molding of large containers.

The high load melt mass flow rate referred to in the present invention is measured at 190 ° C. under a load of 21.60 kg based on JIS K6760 (2000).

The melt tension referred to in the present invention is a capillary rheometer (trade name Capillograph, manufactured by Toyo Seiki Seisaku-sho, Ltd.) at 190 ° C. and a capillary length of 8 m.
m, using a die with a diameter of 2.095 mm, extrusion speed 10 mm / min, take-up speed 0.5-10 m / mi
It is measured under the condition of n.

The silane slightly cross-linked olefin resin of the present invention can be obtained, for example, by a method of forming a cross-link in the presence of a silanol condensation catalyst from a silane-modified olefin resin which is an olefin resin modified with a silane compound. At that time, the addition amount of the silane compound to the silane-modified olefin resin is 0.00 relative to the total weight of the olefin resin in order to crosslink to the extent that gel is not generated.
It is preferably from 1 to 0.5% by weight.

The olefin resin constituting the silane-modified olefin resin is not particularly limited as long as it belongs to the category called olefin resin, for example, ethylene, propylene, 1-butene, 1-hexene, 1 -A polymer obtained by homopolymerizing or copolymerizing olefins such as octene and 4-methyl-1-pentene, and polyethylene, ethylene-propylene copolymer, ethylene-1-
Hexene copolymer, ethylene-1-butene copolymer, polypropylene, poly (4-methyl-1-pentene) and the like can be mentioned, and further ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer. Etc. can also be mentioned. Then, the silane-modified olefin resin is a silane compound in which an alkoxyl group is bonded to silicon is contained in the olefin resin,
The silane-modified olefin resin is, for example, a method of copolymerizing an olefin and an organic unsaturated silane compound, a method of melt-kneading an organic unsaturated silane compound with a radical initiator and graft-copolymerizing an organic unsaturated silane compound on an olefin resin. And the like.

The organic unsaturated silane compound which can form the silane-modified olefin resin has a general formula RR '.
SiY ₂ (R is a monovalent olefinically unsaturated hydrocarbon group,
Y represents a hydrolyzable organic group, R'represents a monovalent hydrocarbon group other than an aliphatic unsaturated hydrocarbon or the same as Y. ). Among them, it is preferable to use an organic unsaturated silane represented by the general formula RSiY _{3 in} which R ′ is the same as Y, and examples thereof include vinyltrimethoxysilane and vinyltriethoxysilane. , Vinyltributoxysilane, allyltrimethoxysilane, allyltriethoxysilane and the like.

The content of the silane compound in the silane-modified olefin resin is such that the silane slightly cross-linked olefin resin obtained by the cross-linking reaction has a high melt tension and excellent processability, and the appearance of the product when subjected to molding From the standpoint of superiority, it is preferably 0.001 to 0.5% by weight, and particularly preferably 0.01 to 0.1% by weight.

The silane finely crosslinked olefin resin of the present invention is produced by, for example, forming fine crosslinks by dehydration condensation of silanol groups produced by hydrolysis of alkoxyesterified silanol groups introduced into a silane-modified olefin resin. Can be done. It is also possible to use a silanol condensation catalyst to accelerate the dehydration condensation reaction.

The silanol condensation catalyst that may be used in the dehydration condensation reaction is not particularly limited as long as it is a compound generally used as a catalyst for promoting dehydration condensation between silanols, and examples thereof include dibutyltin dilaurate and dioctyltin. Compounds such as dilaurate, dibutyltin diacetate, dibutyltin dioctoate, stannous acetate, cobalt naphthenate, lead naphthenate, ethylamine, dibutylamine, hexylamine, pyridine; inorganic acids such as sulfuric acid, hydrochloric acid; acetic acid, maleic acid, etc. And the like, and dibutyltin dilaurate and dioctyltin dilaurate are particularly preferable. The amount of the silanol condensation catalyst used at this time is preferably 0.001 to 1% by weight, more preferably 0.005 to 0.1% by weight.

As the method for producing the silane lightly crosslinked olefin resin of the present invention, any method may be used as long as the silane lightly crosslinked olefin resin of the present invention can be obtained. For example, an olefin resin, a radical initiator, a silane compound, A method of hot water treatment after mixing with a silanol condensation catalyst, a method of steam treatment, or a temperature higher than the melting temperature of the olefin resin by adding an inorganic substance whose heating loss at 200 ° C. by thermogravimetric analysis is 5% by weight or more. Melt kneading, or a method in which a silane-modified olefin resin is subjected to hot water treatment in the presence of a silanol condensation catalyst, a steam treatment, or an inorganic substance having a weight loss upon heating at 200 ° C. of 5% by weight or more by thermogravimetric analysis. And a method of melt-kneading at a temperature equal to or higher than the melting temperature of the silane-modified olefin resin. And the aspect of the method of hot water treatment and steam treatment is not particularly limited, and for example, a silane-modified olefin resin containing a silanol condensation catalyst may be used in an amount of 80 to 10
A method in which a silane-modified olefin resin containing a silanol condensation catalyst is exposed under steam by immersing it in hot water in a reaction tank kept at 0 ° C and holding it for several hours to carry out hydrolysis and dehydration condensation reaction of silane. Examples thereof include a method of causing decomposition and dehydration condensation reaction.

Further, an inorganic substance having a weight loss on heating at 200 ° C. of 5% by weight or more by thermogravimetric analysis is capable of releasing a sufficient amount of water to cause a crosslinking reaction at the melting temperature of the silane-modified olefin resin. Inorganic substances that can be used, and examples of such inorganic substances include uncalcined zeolite, hydrotalcite, hydrous silicic acid, hydrous calcium silicate, and hydrous aluminum silicate.
Then, as the method for producing the silane slightly crosslinked olefin-based resin of the present invention, the step of hot water treatment or steam treatment at the time of performing the slightly crosslinked step can be omitted, and the molding process can be efficiently performed together with simplifying the step. Therefore, it is possible to add a silanol condensation catalyst and an inorganic substance whose loss on heating at 200 ° C. by thermogravimetric analysis is 5% by weight or more to the silane-modified olefin-based resin so that the temperature is not less than the melting temperature of the silane-modified olefin-based resin. The method of melt-kneading is preferable. In addition, the weight loss on heating at 200 ° C by thermogravimetric analysis was 5% by weight.
As the amount of the above-mentioned inorganic substances added, a sufficient amount of water necessary for the crosslinking reaction is released and does not have a great influence on the physical properties of the silane-modified olefin resin. 0.1 to 10% by weight is preferable.

The melt-moldable silane finely crosslinked olefin resin of the present invention has excellent fluidity and moldability, and particularly has excellent product appearance, rigidity and impact resistance when subjected to hollow molding of a large container. Since the product is obtained, the gel fraction is 3% by weight or less, and JIS K6922-1 (2
000-year) density is 940-965k
g / m ³ is preferable, and more preferably 950 to 965.
kg / m ³ and JIS K6922-1 (200
High load melt mass flow rate measured using a load of 21.60 kg based on 0 years) is 1 to 10 g / 10 mi.
The range of n is preferable, and more preferably 3 to 8 g / 10.
It is in the range of min, and the relationship between the high load melt mass flow rate and the melt tension measured at 190 ° C. is the above general formula (2).
It is preferable that the silane finely cross-linked ethylene resin satisfies the above condition.

The melt-moldable silane finely crosslinked olefin resin of the present invention is excellent in fluidity and melt tension, and is therefore a hollow molded product such as a plastic drum, a plastic bottle or the like, or an inflation film, a cast film or the like film. It is especially suitable for the use of.

[0030]

EXAMPLES The present invention will be described below with reference to examples, but these are merely examples and the present invention is not limited thereto.

The resin evaluation method will be described below. <High load melt mass flow rate (HLMFR)> JI
190 based on SK6922-1 (2000)
The measurement was performed at 21 ° C. and a load of 21.60 kg. <Density> Based on JIS K6922-1 (2000), it measured with the density gradient tube. <Melt tension> A capillary rheometer (trade name: Capillograph, manufactured by Toyo Seiki Seisaku-sho, Ltd.) was used at 190 ° C., using a die having a capillary length of 8 mm and a diameter of 2.095 mm, an extrusion speed of 10 mm / min and a take-up speed of 0. The measurement was performed under the condition of 5 to 10 m / min. <Gel Fraction> The sample was extracted with xylene at 120 ° C. for 12 hours and then filtered through a 200-mesh wire net to obtain a filtration residue of 105
After drying for 5 hours in a vacuum dryer at ℃, weighed, and the ratio of the filter residue to the sample amount before treatment was expressed as a percentage. <Product Appearance> The surface condition of the extruded strands in the melt tension measurement was visually observed. <Moldability> A resin for evaluation was extruded by a 115 mmφ extruder manufactured by JSW, a large container was hollow-molded using a mold having a capacity of 100 L, and the moldability was visually evaluated. <Preparation of polymer> Polyethylene (I) was prepared as follows.
And (II) were prepared and used in Examples and Comparative Examples. (1) Preparation of solid catalyst component (A) 108.2 g (1.80 mol) of i-propanol and 134.6 g (1.82 mol) of n-butanol were placed in a 10 L stainless steel autoclave equipped with a stirrer. , Iodine 2.0g, magnesium metal powder 40
g (1.65 mol) and titanium tetrabutoxide 22
4.1 g (0.66 mol) was added, and hexane 2.
After adding 0 L, the temperature was raised to 80 ° C., and the mixture was stirred for 1 hour under a nitrogen blanket while eliminating generated hydrogen gas. Subsequently, the temperature was raised to 120 ° C and the reaction was performed for 1 hour.
A homogeneous solution containing The internal temperature of the autoclave is 45 ° C
Then, 1.32 kg (3.3 mol) of a 30% hexane solution of diethylaluminum chloride was added over 1 hour. After adding all, it stirred at 60 degreeC for 1 hour. Next, 197.0 g (3.3 g atom of silicon) of methylhydropolysiloxane (viscosity of 30 centistokes at 25 ° C.) was added, and the mixture was reacted under reflux for 1 hour. 45 ° C
After cooling to 50% of i-butylaluminum dichloride.
% Hexane solution (2.81 kg, 9.1 mol) was added over 2 hours. After all the ingredients were added, the mixture was stirred at 70 ° C. for 1 hour to obtain a solid catalyst component (A) having a Ti content of 11 wt%. The obtained solid catalyst component (A) was used as hexane slurry in the next polymerization step after removing unreacted substances and by-products that remained by using hexane. (2) Polymerization of polyethylene (I) In a first polymerization vessel having an internal volume of 370 L, 183 L / hr of dehydrated and purified hexane, 18 mmol / hr of tri-i-butylaluminum as an organoaluminum compound (B),
While continuously supplying the solid catalyst component (A) at a rate of 0.26 g / hr and discharging the polymerization content at a required rate,
At 85 ° C., ethylene was supplied at a rate of 20.3 kg / hr, the ethylene concentration was kept at 1.56 wt% and the hydrogen concentration ratio to ethylene was kept at 0.27 mol / mol, and the total pressure was 2.9 M.
Under the conditions of PaG and an average residence time of 1.81 hr, the first-stage polymerization was continuously performed in a liquid-filled state. The hexane slurry containing the polymer obtained in the first polymerization vessel had a pressure of 59 KP.
aG, a temperature of 70 ° C., and an unreacted hydrogen and ethylene were continuously sent to one depressurizing tank having an average residence time of 0.6 hr to flush unreacted hydrogen and ethylene (MFR of the polymer in the first stage was 1
4.8 g / 10 min). Then, the mixture was introduced into a second polymerization vessel having an internal volume of 545 L, the solid catalyst component and the alkylaluminum were not added, and 113 L / hr of hexane was supplied, and ethylene was discharged at 80 ° C. while discharging the content of the polymerization vessel at a required rate. Supply at a rate of 20.7 kg / hr, ethylene concentration 0.75 wt%, hydrogen to ethylene concentration ratio 0.0
The second stage polymerization was carried out under the conditions of a total pressure of 2.0 MPaG and an average residence time of 0.60 hr while maintaining the amount at 33 mol / mol.
The slurry from the second polymerization vessel has a pressure of 5 in one depressurization tank.
9 KPaG, temperature 70 ° C., average residence time 1.0 hr,
After flushing unreacted hydrogen and ethylene, separation
Through the drying process, a polymer powder having an HLMFR of 9.3 g / 10 min was obtained. (3) In a first polymerization vessel having a polymerization inner volume of 370 L of polyethylene (II), 150 L / hr of dehydrated and purified hexane and 36 mmol / hr of tri-i-butylaluminum as the organoaluminum compound (B),
While continuously supplying the solid catalyst component (A) at a rate of 0.43 g / hr and discharging the polymerization content at a required rate,
At 85 ° C., ethylene was supplied at a rate of 19.0 kg / hr, the ethylene concentration was kept at 0.78 wt%, and the hydrogen concentration ratio to ethylene was kept at 0.258 mol / mol, and the total pressure was 2.9.
The first-stage polymerization was continuously performed in a liquid-filled state under the conditions of MPaG and an average residence time of 2.1 hours. The hexane slurry containing the polymer obtained in the first polymerization vessel had a pressure of 59 KPa.
G, the temperature was 70 ° C., and the unreacted hydrogen and ethylene were continuously sent to one depressurization tank having an average residence time of 0.8 hr to flush unreacted hydrogen and ethylene (MFR of the polymer in the first stage was 0.9.
7 g / 10 min). Then, a hexane slurry containing a polymer was introduced into a second polymerization vessel having an internal volume of 545 L, hexane 146 L / hr was supplied without adding a solid catalyst component and alkylaluminum, and the content of the polymerization vessel was discharged at a required rate. However, at 80 ° C, 21.0 kg of ethylene /
The second stage polymerization is carried out under the conditions of a total pressure of 2.0 MPaG and an average residence time of 1.6 hr while maintaining the ethylene concentration at 1.53 wt% and hydrogen at an ethylene concentration ratio of 0.046 mol / mol at a rate of hr. It was Slurry from the second polymerization vessel, pressure 59KPaG, temperature 70 ℃ in one depressurization tank,
After flushing unreacted hydrogen and ethylene with an average residence time of 1.2 hr, HLMF was separated through a separation and drying process.
A polymer powder having R of 5.0 g / 10 min was obtained.

Example 1 Linear high-density polyethylene (I) in the form of powder polymerized in the above process (density 956 kg / m ³ , HLMFR 9.3)
g / 10 min) with 0.04% by weight of vinyltrimethoxysilane (trade name KBM-1003, manufactured by Shin-Etsu Chemical Co., Ltd.) and 2,5-dimethyl-2,5-bis (t-butylperoxy) as an organic peroxide. ) Hexane (made by NOF CORPORATION,
0.002% by weight of trade name Perhexa 25B) and 0.002% by weight of dibutyltin dilaurate (manufactured by Wako Pure Chemical Industries, Ltd.) as a silanol condensation catalyst are mixed, and the screw diameter is 2
The mixture was put into a 0 mm, L / D = 25 single-screw extruder (manufactured by Toyo Seiki Seisakusho, trade name Labo Plastomill 30C-150), melt-kneaded at 200 ° C., and then pelletized. The pellets were treated in hot water at 80 ° C. for 3 days to allow the fine crosslinking reaction to proceed, and a silane finely crosslinked olefin resin was obtained.

The obtained silane slightly crosslinked olefin resin has a high load melt mass flow rate of 4.8 g / 10 mi.
n, melt tension 490 mN, gel fraction 0.4% by weight, and the surface appearance of the obtained strand was good. Molding workability was good with no unevenness in wall thickness due to drawdown, poor appearance due to rough skin, and poor fusion during pinching. The results are shown in Table 1.

[0034]

[Table 1] Comparative Example 1 The blending amount of vinyltrimethoxysilane was 0.04% by weight to 0.08% by weight, and the blending amount of 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane was 0.0.
Synthesis was performed in the same manner as in Example 1 except that the content was changed from 02% by weight to 0.004% by weight.

The obtained silane-crosslinked olefin resin has a high load melt mass flow rate of 0.5 g / 10 min,
The melt tension was 590 mN and the gel fraction was 3.6% by weight, and the surface appearance of the obtained strand was poor. Molding processability was poor because the surface roughness of the molded product and defective fusion of pinches occurred. The results are shown in Table 1.

Comparative Example 2 Powder-like linear high-density polyethylene (II) polymerized in the above step (density 952 kg / m ³ , HLMFR5.
0 g / 10 min) was used.

The resin had a melt tension of 250 mN and a gel fraction of 0.4% by weight, and the surface appearance of the obtained strand was good. The moldability was poor because the thickness of the molded body became non-uniform due to drawdown of the extruded resin. The results are shown in Table 1.

Comparative Example 3 Linear high-density polyethylene (I) in powder form polymerized in the above process (density 956 kg / m ³ , HLMFR 9.3).
g / 10 min) and 0.02 weight of α, α′-bis (t-butylperoxydiisopropyl) benzene (product name Perbutyl P manufactured by NOF CORPORATION) as an organic peroxide, and screw diameter 20 mm, L / D = 25 single-screw extruder (manufactured by Toyo Seiki Seisakusho, trade name Labo Plastomill 30C-
150) and melt-kneaded at 200 ° C. to obtain crosslinked polyethylene pellets.

The cross-linked polyethylene obtained had a high load melt mass flow rate of 4.5 g / 10 min and a melt tension of 3
The surface appearance of the obtained strand was good, with a gel fraction of 30 mN and a gel fraction of 0.5% by weight. The moldability was poor because the thickness of the molded body became non-uniform due to drawdown of the extruded resin. The results are shown in Table 1.

Example 2 Linear high-density polyethylene (I) in the form of powder polymerized in the above process (density 956 kg / m ³ , HLMFR 9.3).
g / 10 min) with 0.04% by weight of vinyltrimethoxysilane (trade name KBM-1003, manufactured by Shin-Etsu Chemical Co., Ltd.) and 2,5-dimethyl-2,5-bis (t-butylperoxy) as an organic peroxide. ) Hexane (made by NOF CORPORATION,
Brand name Perhexa 25B) 0.002% by weight is blended,
Single screw extruder with a screw diameter of 20 mm and L / D = 25 (manufactured by Toyo Seiki Seisakusho, trade name Labo Plastomill 30C-15
0) and melt-kneaded at 200 ° C. to pelletize the silane-modified polyethylene. To 100 parts by weight of the pellet, 0.2 wt% of dibutyltin dilaurate (manufactured by Wako Pure Chemical Industries, Ltd.) as a silanol condensation catalyst was added to the above-prepared straight-chain high-density polyethylene, uncalcined zeolite (manufactured by Eishin Kasei, trade name) CS-100; Heat loss at 200 ° C. by thermogravimetric analysis 15%) 5 parts by weight of a masterbatch containing 1.0% by weight was blended, and melt-kneaded again at 200 ° C. by an extruder to carry out hot water treatment. Without this, a silane slightly crosslinked olefin resin was obtained.

The obtained silane slightly crosslinked olefin resin has a high load melt mass flow rate of 5.0 g / 10 mi.
n, melt tension 390 mN, gel fraction 0.8% by weight, and the surface appearance of the obtained strand was good. The results are shown in Table 1.

Comparative Example 4 Synthesis was carried out in the same manner as in Example 2 except that uncalcined zeolite was not added.

The obtained silane-crosslinked olefin resin has a high load melt mass flow rate of 7.4 g / 10 min,
The melt tension was 220 mN and the gel fraction was 0.4% by weight, and the surface appearance of the obtained strand was good. The moldability was poor because the thickness of the molded body became non-uniform due to drawdown of the extruded resin. The results are shown in Table 1.

A graph showing the relationship between HLMFR and melt tension in Table 1 is shown in FIG.

Example 1 has almost the same HLMFR as Comparative Examples 2 and 3, but the melt tension is greatly improved, and the moldability during hollow molding is good. Further, in Comparative Example 1 in which the gel fraction exceeded 3% by weight, the extruded strand was in the state of melt fracture, and the moldability deteriorated.

Example 2 in which uncalcined zeolite was added
Has a clearly higher melt tension than Comparative Example 4,
Silane cross-linking can be performed without a post-process such as hot water treatment.

[0047]

EFFECTS OF THE INVENTION The silane slightly crosslinked olefin-based resin of the present invention, when compared with a conventional uncrosslinked olefin-based resin or a crosslinked olefin-based resin obtained by crosslinking and modifying an olefin-based resin with an organic peroxide, It is possible to provide a resin having a high fluidity and a high melt tension, and it is possible to realize good processability in hollow molding and the like.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between HLMFR and melt tension in Table 1.

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Claims (5)

[Claims] 1. A gel fraction of 3% by weight or less, JIS
21.60 kg based on K6922-1 (2000)
A melt-moldable silane finely crosslinked olefin-based resin, characterized in that the relationship between the high load melt mass flow rate measured using the load and the melt tension measured at 190 ° C. satisfies the following general formula (1). MS ≧ 550 × e ^{−0.108 × (HLMFR)} (1) (where MS is melt tension (unit is mN), HLMFR
Is a high load melt mass flow rate (unit: g / 10mi
n) and e indicate the base of the natural logarithm. ) 2. The gel fraction is 3% by weight or less, JIS
The density measured based on K6922-1 (2000) is 940 to 965 kg / m ³ , JIS K6922-1
High load melt mass flow rate measured with a load of 21.60 kg based on (2000) is 1 to 10 g /
The silane finely crosslinked ethylene resin having a relationship between the high load melt mass flow rate and the melt tension measured at 190 ° C. in the range of 10 min and satisfying the following general formula (2) is a silane finely crosslinked ethylene resin. Melt-moldable silane finely crosslinked olefin resin. MS ≧ 615 × e ^{−0.108 × (HLMFR)} (2) (where MS is melt tension (unit is mN), HLMFR
Is a high load melt mass flow rate (unit: g / 10mi
n) and e indicate the base of the natural logarithm. ) 3. An olefin resin containing 0.001 of a silane compound.
A silane-modified olefin resin modified by blending 1 to 0.5% by weight with 0.001 to 1% by weight of a silanol condensation catalyst and subjected to hot water treatment, steam treatment, or thermogravimetric analysis Heating loss at 200 ℃ by 5
The melt-moldable silane finely cross-linked olefin resin according to claim 1 or 2, wherein the cross-linking is finely cross-linked by a method selected from a method of adding an inorganic substance in an amount of not less than wt% and performing melt-kneading treatment. Production method. 4. A hollow molded article characterized by comprising the melt-moldable silane finely crosslinked olefin resin according to claim 1 or 2. 5. A film comprising the melt-moldable silane finely crosslinked olefin resin according to claim 1 or 2.