JPH11181164A - Crosslinkable olefin based resin composition and preparation of crosslinked pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain (1) an olefin based resin composition for producing crosslinked pipes less forming gum in the die land in producing crosslinked pipes of an olefin based resin by extrusion molding and (2) a process for producing crosslinked pipes from this resin composition. SOLUTION: This olefin based resin composition for producing crosslinked pipes comprises 100 pts.wt. silane crosslinkable olefin based resin; 0.05-20 pts.wt. master batch composed of 100 pts. olefin based resin and 0.1-10 pts.wt. silanol condensation catalyst; and 0.005-3 pts.wt. fluorine based elastomer or fluorine based plastic. Crosslinked pipes can be produced from these resin compositions by the extrusion molding method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a crosslinkable polyolefin resin composition and a method for producing a crosslinked tube (tube) from the resin composition. In particular, when producing a crosslinked pipe made of a polyolefin resin by an extruder molding method, when producing a crosslinked olefin resin composition for producing a crosslinked pipe with less occurrence of eye drop, and when producing a crosslinked pipe from this composition The present invention also relates to a method for producing an olefin-based resin cross-linked tube with less occurrence and accumulation of metal tar on a metal wall (die land) at a molten resin outlet of a die.

[0002]

2. Description of the Related Art Conventionally, when a crosslinked tube (tube) is produced from a crosslinkable olefin resin composition by an extrusion molding method,
When extruding molten resin from the die attached to the extruder tip,
Dust (burned resin, low molecular weight compounds, additives, etc., which accumulates at the die exit with the elapse of molding time) is generated on the metal wall (die land) at the exit of the molten resin of the die, and gradually accumulates over time. As the accumulated amount increases, it adheres to the surface of the crosslinked tube as a product, and not only deteriorates the appearance of the crosslinked tube, but also causes a hole in the wall surface of the crosslinked tube in some cases.

Conventionally, there are two methods for preventing the generation of tarnish on a die land when manufacturing a resin pipe: (1) a method of lowering the temperature of a molten resin as much as possible; Is added. However, in the method (1), since the molten resin is extruded at a low temperature, the die-casting is certainly reduced, but on the other hand, the smoothness of the surface of the resin tube of the obtained product is deteriorated, and shark skin (shark) is reduced. −x-skin), and the appearance of the resin tube of the product deteriorates. In addition, in order to reduce the occurrence of eye stains, a method of blending an eyelash reducing agent such as magnesium stearate or calcium stearate with a raw material resin has been proposed and put to practical use.

According to an experiment conducted by the present inventors, the method of adding a stearic acid-based compound as a stain-reducing agent to a raw material resin is effective when the raw material resin is a non-crosslinkable olefin resin composition. However, it was found that when the starting resin was a silane-crosslinkable olefin-based resin composition, a remarkable reduction in the dent was not exhibited. As a result of investigating the cause, when the raw material resin is a silane-crosslinkable olefin-based resin composition, the silane-crosslinkable olefin-based resin adheres to the die land of a die attached to the tip of the extruder, and these adhered substances are kept at a high temperature for a long time. It is presumed that they are thermally degraded and decomposed by exposure to, causing the occurrence of eye tarnish.

[0005]

SUMMARY OF THE INVENTION In view of the above situation, the present inventor has made intensive studies to provide a technique which has solved the above-mentioned drawbacks all at once, and as a result, has completed the present invention. That is, the objects of the present invention are as follows. 1. An object of the present invention is to provide a resin composition for producing a crosslinked tube which is less likely to cause eye drop when producing a crosslinked tube made of an olefin resin by an extruder molding method. 2. An object of the present invention is to provide a method for producing a crosslinked pipe made of an olefin resin by an extrusion molding method, in which the generation and accumulation of die build-up on a metal wall (die land) at a die outlet is reduced.

[0006]

According to the present invention, there is provided a silane-crosslinkable olefin resin, comprising:
Parts by weight, 0.5 to 20 parts by weight of a master batch comprising 100 parts by weight of an olefin resin and 0.1 to 10 parts by weight of a silanol condensation catalyst, and 0.005 parts by weight of a fluorine-based elastomer or a fluorine-based resin. The present invention provides a crosslinkable olefin-based resin composition for producing a crosslinked tube, characterized in that the composition contains 3 to 3 parts by weight.

Further, in the present invention, 100 parts by weight of the silane-crosslinkable olefin resin is added to the olefin resin 100 parts by weight.
0.5 to 20 parts by weight of a master batch consisting of 0.1 to 10 parts by weight of a silanol condensation catalyst and 0.0010 parts by weight of a fluoroelastomer or a fluororesin are added thereto.
An olefin-based resinous cross-linking tube characterized in that a resin composition containing 5 to 3 parts by weight is melt-kneaded with an extruder, extruded into a tube with a circular die attached to the tip of the extruder, and cooled and solidified. And a method for producing the same.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
In the present invention, the silane crosslinkable olefin resin refers to an olefin resin containing a vinylsilane group in a molecule. As the olefin resin, polypropylene, polyethylene or ethylene and a small proportion (generally 0.1 to 1)
5% by weight, preferably 0.5 to 6% by weight) of propylene and / or a copolymer with butene. More specifically, the density is 0.862 to 0.965.
g / cm ² and melt index of 0.01 to 60 g / 1
0 minutes, preferably 0.1 to 25 g / 10 minutes, an ethylene-based resin such as ultra-low density polyethylene, low density polyethylene, linear low density polyethylene, medium / low density polyethylene, or high density polyethylene; An ethylene / vinyl acetate copolymer having an acrylic acid content of 0.1 to 25% by weight, an ethylene / acrylic acid copolymer having an acrylic acid content of 0.1 to 25% by weight,
Polypropylene, propylene / ethylene (0.5-10
Wt%) copolymer, propylene / butene-1 copolymer,
Pyrene resin such as propylene / hexene-1 copolymer, polybutene, ethylene / propylene rubber (EP
R), ethylene propylene diene monomer (EPD)
M) and the like.

To impart silane crosslinkability to the olefin resin, (i) a method of graft copolymerizing a vinylsilane compound with an olefin polymer, (ii) a method of randomly copolymerizing ethylene and a vinylsilane compound, and the like. Can be. Examples of the vinylalkoxysilane compound include vinyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and the like. For details of the method for producing these silane-crosslinkable (modified) olefin-based resins, see, for example, JP-B-48-171.
No. 1, JP-A-55-9611, JP-A-59-9611
No. 36115, etc., and can be obtained on the market.

In order to crosslink the silane-crosslinkable olefin resin, a silanol condensation catalyst such as dibutyltin dilaurate is blended with the silane-crosslinkable olefin resin, and water is added. Thus, a cross-linking reaction can easily be caused to cause cross-linking. The silanol condensation catalyst is not directly mixed with the silane-crosslinkable olefin resin, but as a masterbatch mixed with the olefin resin as the base. If the silanol condensation catalyst is directly blended, it is difficult to uniformly disperse the catalyst in the olefin resin, and the crosslinking may be localized, which is not preferable.

In the masterbatch, a silanol condensation catalyst is used in an amount of 0.1 to 100 parts by weight of the base olefin resin.
10 parts by weight are contained. When the amount of the silanol condensation catalyst is 0.
If it is less than 1 part by weight, the concentration is too low to function as a masterbatch. If it exceeds 10 parts by weight, it is difficult to mix it with the base resin, and both are not preferred. The amount of the master batch depends on the concentration of the silanol condensation catalyst in the master batch, but the master batch is 0.5 to 20 parts by weight based on 100 parts by weight of the silane crosslinkable olefin resin.
It shall be selected in the range of parts by weight. If the concentration of the silanol condensation catalyst in the masterbatch is low, increase the blending amount of the masterbatch.If the concentration is high, reduce the blending amount of the masterbatch and melt the silane-crosslinkable olefin resin composition. The degree of crosslinking measured according to JIS C3005 after crosslinking is preferably 2% by weight or more. Above all, it is preferably at least 4% by weight, particularly preferably 4 to 90% by weight.

The resin composition according to the present invention further contains a fluorine-based elastomer or a fluorine-based resin.
When a fluorine-based elastomer or a fluorine-based resin is contained, the mechanism of action when the resin composition is melt-kneaded and extruded as a cross-linking tube is unknown, but the metal wall (die land) at the die outlet is not covered with a metal. Can be reduced.

In the present invention, the term "fluoroelastomer" means a polymer or copolymer elastomer containing at least one fluorine atom on average in a unit monomer. For example, a copolymer of ethylene trifluoride chloride and vinylidene fluoride (for example, trade name: KelF elastomer), a copolymer of vinylidene fluoride and propylene hexafluoride (for example, trade names: Viton, Florel) ). Further, in the present invention, the fluororesin is
Tetrafluoroethylene resin, trifluorinated ethylene resin, 4
Fluorinated ethylene hexafluoropropylene resin (fluorinated ethylene propylene), vinylidene fluoride resin, and the like.

The mixing ratio of the fluorine-based elastomer or the fluorine-based resin to the silane-crosslinkable olefin-based resin is as follows:
For 100 parts by weight of the silane crosslinkable olefin resin,
It should be selected in the range of 0.005 to 3 parts by weight. If the compounding ratio is less than 0.005 parts by weight, the effect of reducing eye repelling is not seen, and if it exceeds 3 parts by weight, the crosslinkability becomes too high, and neither is preferable. Within the above range, 0.0
1 to 0.5 parts by weight is particularly preferred.

The above-mentioned fluorine-based elastomer or fluorine-based resin is also preferably blended as a masterbatch blended with the olefin-based resin as the base material, rather than directly blended with the silane-crosslinkable olefin-based resin. When a fluorine-based elastomer or a fluorine-based resin is directly blended, it is difficult to uniformly disperse the fluorine-based elastomer or the fluorine-based resin in the silane-crosslinkable olefin-based resin. The concentration of the master batch is
0.5 to 30 parts by weight of a fluorine-based elastomer or a fluorine-based resin with respect to 100 parts by weight of an olefin-based resin serving as a substrate.
It is preferred to select in the range of parts by weight.

The resin composition according to the present invention is a mixture of the above-described components in the proportions described above. The resin composition may further contain other components, if necessary, for example,
Dispersants, lubricants, heat stabilizers, antioxidants, UV absorbers,
Various resin additives such as an antistatic agent, a copper damage inhibitor, a flame retardant, a dye, a pigment, a filler and a foaming agent can be blended. To prepare the resin composition according to the present invention, the essential components, other components and the like are weighed in a predetermined amount, and blended using a conventionally known blending device such as a blender, a tumbler, a mixer, or a mixing device. Good. The resin composition may be in the form of a dry blend, and may be dry-blended into a melt-kneaded mixture of some components and the remaining components. The master batch of the silanol condensation catalyst was not melt-kneaded with other resin composition components, but was previously melt-kneaded with a component not containing the silanol condensation catalyst. It is good to dry blend the master batch.

In order to form a crosslinked tube (tube) from the resin composition according to the present invention, the above resin composition is melt-kneaded by an extruder, extruded into a tube by a circular die attached to the extruder tip, and cooled. Or solidification by cooling with cold air. A cross-linking reaction occurs when the resin composition is melt-kneaded, and the cross-linking reaction proceeds slowly even after the tube is manufactured by heating with steam or the like, depending on the amount of the vinylsilane group and the compounding amount of the silanol condensation catalyst. A crosslinked tube having a high degree of crosslinking can be obtained. The bridge pipe can be used for piping for hot and cold water supply of buildings such as ordinary houses and hotels, piping for heating fluid for floor heating, and piping for functional oil of vehicles such as automobiles.

[0018]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following description unless it exceeds the gist. In the examples described below, various evaluation tests were performed as follows.

1. Eye drop removal frequency: The length of the tube that can be manufactured before the eye drop needs to be removed in order to prevent the eye dust deposited on the tube (tube) die land from adhering to the surface of the pipe. It means that the longer the length, the smaller the amount of eye stains deposited. 2. Degree of crosslinking (%): Measured according to JIS K6769 for a crosslinked tube (tube) 48 hours after production. 3. Tensile yield point strength (kgt / cm2): Measured according to JIS K6769 for a crosslinked tube (tube) 48 hours after production. 4. Elongation at break (%): Measured according to JIS K6769 for a crosslinked tube (tube) 48 hours after production.

[Examples 1 and 2] <Preparation of resin composition> Silane crosslinkable polyethylene (manufactured by Mitsubishi Chemical Corporation, trade name: Linklon XLE830N, medium density polyethylene obtained by graft copolymerization of vinyltrimethoxysilane) 100 parts by weight of linear low-density polyethylene (manufactured by Nippon Polychem Co., Ltd., trade name: Novatec UF421)
5 parts by weight of a master batch composed of 100 parts by weight and 1 part by weight of dioctyltin dilaurate was mixed with 100 parts by weight of high-density polyethylene and a fluorine-based elastomer.
(Manufactured by Sumitomo 3M Limited, trade name: Dynam-PPA F
X-5920) was mixed with 5 parts by weight of a master batch to prepare a silane-crosslinkable polyethylene composition which was blended so that the amount of the fluorinated elastomer was as shown in Table 1.

<Manufacture and evaluation test of tube> At the end of a full-flight screw extruder (L / D = 24, 50 mm diameter), a tube (tube) having an outer diameter of 13 mm and a wall thickness of 1.5 mm was placed.
A production die was attached, the resin composition was melted at 200 ° C., and extruded at an extrusion speed of 10 m / min to produce a tube. The measurement results such as the frequency of removing eye tar during pipe production, the degree of crosslinking of the obtained crosslinked pipe, the tensile yield point strength, and the elongation at break,
It is shown in Table 1.

[Comparative Examples 2 and 3] In the examples described in Example 1, the one in which a fluorine-based elastomer was not added (Comparative Example 1), and 100 parts by weight of high-density polyethylene and stearin were used instead of the fluoroelastomer. Magnesium acid E
MS-6P (trade name: AP-600, manufactured by Seishin Kasei Co., Ltd.)
0.15 parts by weight of a resin composition (Comparative Example 2);
Resin compositions (Comparative Example 3) each containing 2 parts by weight were prepared. Using these resin compositions as raw materials, pipes were manufactured in the same procedure as described in Example 1. Table 1 shows the measurement results such as the frequency of removing the dents during the production of the tube, the degree of crosslinking of the obtained tube, the tensile yield strength, and the elongation at break.

[0023]

[Table 1]

From Table 1, the following becomes clear. (1) In the case of producing a crosslinked tube by extrusion molding using a silane crosslinkable polyethylene composition as a raw material, the occurrence of tarnish on the die land is small, and it is not necessary to frequently remove the tarnish from the dieland ( Example 1, Example 2, Comparative Example 1). (2) In contrast, when the silane crosslinkable polyethylene composition is blended with magnesium stearate, which has been conventionally effective as an eye tarnish reducing agent, the effect of reducing the occurrence and accumulation of eye tarnish on the die land is almost zero. Not exhibited (see Comparative Examples 2 and 3).

Example 3 <Preparation of Resin Composition> To 100 parts by weight of silane crosslinkable polyethylene (manufactured by Mitsubishi Chemical Corporation, trade name: Linklon XHE740N, high-density polyethylene obtained by graft copolymerization of vinyltrimethoxysilane). , High density polyethylene (trade name: Novatec HJ360, manufactured by Nippon Polychem) 100
5 parts by weight of a master batch consisting of 1 part by weight of dioctyltin dilaurate, 100 parts by weight of high-density polyethylene and a fluorine-based elastomer (Dynama-PPA, manufactured by Sumitomo 3M Limited) FX-5920)
A silane crosslinkable polyethylene composition (dry blend) was prepared by blending a master batch consisting of 5 parts by weight and blending the fluorine-based elastomer in an amount of 0.075 parts by weight.

<Manufacture of Tube and Evaluation Test> A cross-linked tube was manufactured in the same procedure as in Example 1 using the obtained resin composition as a raw material. Table 2 shows the measurement results such as the frequency of removing the tarnish during the production of the pipe, the degree of crosslinking of the obtained crosslinked pipe, the tensile yield strength, and the elongation at break.

Comparative Example 4 A resin composition was prepared in the same manner as described in Example 1 except that a resin composition was prepared in the same manner as described in Example 3 except that a fluorine-based elastomer was not added. Tubes were manufactured. Table 2 shows the measurement results such as the frequency of removing the tarnish during the production of the pipe, the degree of crosslinking of the obtained crosslinked pipe, the tensile yield strength, and the elongation at break.

[Comparative Examples 5 to 7] 100 parts by weight of non-crosslinkable high density polyethylene (manufactured by Nippon Polychem Co., Ltd., trade name: Novatec HJ360) containing no additives (Comparative Example 5), The master batch of the fluorine-based elastomer (FX-5920) used in Example 1 was blended,
Resin composition blended so that the amount of fluorine-based elastomer is 0.075 parts by weight (Comparative Example 6), resin composition blended with 0.15 parts by weight of magnesium stearate (AP-600P) (Comparative Example) 7) was prepared, and a tube was produced in the same procedure as in Example 1 using each resin composition as a raw material. Table 2 shows the measurement results such as the frequency of removing the tarnish during the production of the pipe, the degree of crosslinking of the obtained crosslinked pipe, the tensile yield strength, and the elongation at break.

[0029]

[Table 2]

From the above Table 2, the following becomes clear. (1) A resin composition in which a fluorinated elastomer is blended with silane-crosslinkable polyethylene has a low appearance of die cast on a die land when a cross-linked tube is produced by an extrusion molding method, and therefore, the frequency of eye die removal from the die land is small. (See Example 3). (2) On the other hand, when the fluorinated elastomer is not blended with the silane-crosslinkable polyethylene, there is a lot of generation and accumulation of eye spots on the die land, and it is necessary to frequently remove the eye spots (see Comparative Example 4). . (3) Also, when the raw material resin is a non-crosslinkable polyethylene,
When a fluorine-based elastomer is added to the mixture, the generation and accumulation of eye drop on the die land is slightly reduced, but not so much as when an eye drop reducing agent is added (see Comparative Examples 5 and 6). (4) When the raw material resin is non-crosslinkable polyethylene, blending magnesium stearate with this significantly reduces the generation and accumulation of eye spots on die lands, but significantly decreases even when blended with crosslinkable polyethylene. No (see Comparative Example 2, Comparative Example 3, and Comparative Example 7).

[0031]

The present invention has been described in detail above, and has the following particularly advantageous effects, and its industrial utility value is extremely large. 1. The crosslinkable olefin resin composition for pipe production according to the present invention is characterized in that, when a pipe (tube) is produced by using this as a raw material by an extruder molding method, the generation and accumulation of die build-up on the die land of the pipe extrusion die is small. A crosslinked pipe made of a polyolefin resin having excellent appearance and high commercial value can be obtained. 2. According to the production method according to the present invention, the generation and accumulation of eye fogging on the die land of the die mounted on the extruder tip is small, and therefore, the number of times of removing the eye filing accumulated on the die land is reduced, and the complexity of removing this is reduced. Is greatly reduced, which is extremely advantageous industrially. 3. ADVANTAGE OF THE INVENTION According to the manufacturing method which concerns on this invention, a poor appearance, such as shark skin (shark skin), does not generate | occur | produce on the obtained product surface, but a crosslinked pipe (tube) made of a polyolefin resin excellent in appearance and high in commercial value is obtained. be able to.

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[Procedure amendment]

[Submission date] January 21, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction contents]

[Examples 1 and 2] <Preparation of resin composition> Silane crosslinkable polyethylene (manufactured by Mitsubishi Chemical Corporation, trade name: Linklon HE707N , medium density polyethylene obtained by graft copolymerization of vinyltrimethoxysilane) 100 parts by weight of linear low-density polyethylene (manufactured by Nippon Polychem Co., Ltd., trade name: Novatec UF421)
5 parts by weight of a master batch composed of 100 parts by weight and 1 part by weight of dioctyltin dilaurate was mixed with 100 parts by weight of high-density polyethylene and a fluorine-based elastomer.
(Manufactured by Sumitomo 3M Limited, trade name: Dynam-PPA F
X-5920) was mixed with 5 parts by weight of a master batch to prepare a silane-crosslinkable polyethylene composition which was blended so that the amount of the fluorinated elastomer was as shown in Table 1.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0025

[Correction method] Change

[Correction contents]

Example 3 <Preparation of Resin Composition> 100 parts by weight of silane crosslinkable polyethylene (manufactured by Mitsubishi Chemical Corporation, trade name: Linklon XE800 , high-density polyethylene obtained by graft copolymerization of vinyltrimethoxysilane) 5 parts by weight of a master batch composed of 100 parts by weight of high-density polyethylene (manufactured by Nippon Polychem Co., Ltd., trade name: Novatec HJ360) and 1 part by weight of dioctyltin dilaurate;
A master batch consisting of 00 parts by weight and 5 parts by weight of a fluorinated elastomer (manufactured by Sumitomo 3M Co., Ltd., trade name: Dynama-PPA FX-5920) is blended, and the amount of the fluorinated elastomer is 0.075. Silane crosslinkable polyethylene composition (dry blended) formulated to be in parts by weight
Was prepared.

Claims (2)

[Claims] A master batch comprising 100 parts by weight of a silane-crosslinkable olefin resin, 100 parts by weight of an olefin resin and 0.1 to 10 parts by weight of a silanol condensation catalyst.
A crosslinkable olefin resin composition for producing a crosslinked tube, comprising 5 to 20 parts by weight and 0.005 to 3 parts by weight of a fluorine-based elastomer or a fluorine-based resin. 2. 100 parts by weight of an olefin resin and 100 parts by weight of a silane-crosslinkable olefin resin
Resin containing 0.5 to 20 parts by weight of a master batch consisting of 0.1 to 10 parts by weight of a condensation catalyst and containing 0.005 to 3 parts by weight of a fluorine-based elastomer or a fluorine-based resin. A method for producing an olefin-based resin crosslinked tube, comprising melt kneading the composition with an extruder, extruding the composition into a tube with a circular die attached to the extruder tip, and cooling and solidifying the composition.