JPH05262934A - Polyolefin resin composition - Google Patents

Abstract

PURPOSE:To provide the polyolefin resin composition usually free from the generation of die tailings when extrusion-molded, excellent in the continuous extrusion molding productivity, and capable of being cross-linked. CONSTITUTION:The polyolefin resin composition is characterized by containing a mixture of a silanol condensation catalyst with an ethylene-ethylenic unsaturated silane compound copolymer having an ethylenic unsaturated silane compound unit content of 0.001-15wt.% and 0.015-0.2 pts.wt. of a vinylidene fluoride rubber based on pts.wt. of the mixture.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a copolymer of ethylene and an ethylenically unsaturated silane compound, wherein the content of the ethylenically unsaturated silane compound unit is 0.5 to 10% by weight. Cross-linking in the presence of water used for extrusion molded products such as electric wires, pipes, home appliances, and automobile parts for the purpose of preventing the generation of die scum that adheres to the front of the die during extrusion molding of the copolymer and silanol condensation catalyst. The present invention relates to a possible polyolefin resin composition.

[0002]

2. Description of the Related Art A copolymer of ethylene and an ethylenically unsaturated silane compound, wherein the content of the ethylenically unsaturated silane compound unit is 0.5 to 10% by weight, is a silanol. It is widely used in the fields of pipe manufacturing, coating of electric wires and cables, home appliances, automobiles, etc. due to the fact that it can be crosslinked by contacting with water in the presence of a condensation catalyst. However, it is a copolymer of ethylene and an ethylenically unsaturated silane compound, and the content of the ethylenically unsaturated silane compound unit is 0.5 to 10% by weight, and the silanol condensation catalyst. When the mixed resin of No. 1 is molded by an extruder, a die scum called an eye die is generated at the front of the die, and the die scum accumulates with the passage of time, impairing the appearance of the product and finally carbonizing and adhering to the product. As a result, mechanical properties are adversely affected and continuous production becomes impossible. Further, in the coating of the electric wire or cable, the carbide adheres to the outer surface of the wire and impairs the appearance of the electric wire or cable. Heretofore, various improvements have been attempted as a method for removing die scum generated during extrusion molding. For example, the treatment of the inner surface of the die and the method of burning it out using a gas burner are also performed.
It was difficult to completely remove it, which was a big problem in production. Particularly in the manufacture of products with a large diameter, it is difficult to burn off the die scum accumulated at the die outlet with a gas burner, and continuous production is impossible. Therefore, continuous production is difficult even though it is a simple cross-linking method originally, so that the cost is increased and it is not necessarily advantageous from the economical aspect.

[0003]

The object of the present invention is to add a vinylidene fluoride rubber to prevent the generation of die scum, and to realize continuous production without deteriorating the appearance and characteristics. Another object of the present invention is to provide a crosslinkable polyolefin resin composition.

[0004]

The present invention is a copolymer of ethylene and an ethylenically unsaturated silane compound, wherein the content of the ethylenically unsaturated silane compound unit is 0.5.
10% by weight of the copolymer and 100 parts by weight of the silanol condensation catalyst, 0.0% vinylidene fluoride rubber.
15 to 0.2 parts by weight of a polyolefin resin composition, wherein the vinylidene fluoride rubber is a copolymer of vinylidene fluoride and propylene pentafluoride, vinylidene fluoride and propylene hexafluoride. Or a vinylidene fluoride-trifluoroethylene copolymer, wherein the vinylidene fluoride rubber is ASTM-D-1.
The Mooney viscosity at 121 ° C. measured according to 614 is 20 to 50 and the molecular weight measured by gel permeation chromatography is 3
The above-mentioned polyolefin resin composition having a viscosity of 10,000 to 70,000.

The copolymer of ethylene and an ethylenically unsaturated silane compound in the present invention is disclosed in JP-A-55-9611.
A polyethylene resin having a silane group introduced into a polyethylene molecule is provided with water-crosslinkability by the method described in Japanese Patent Laid-Open Publication No. As the unsaturated silane compound, various compounds having an ethylenically unsaturated bond copolymerizable with ethylene and a hydrolyzable silane group can be used. If such a compound is represented by a general formula, there is a compound represented by the following formula, for example. RSiR ′ _n Y ₃ − _n (wherein R represents an ethylenically unsaturated hydrocarbyl or hydrocarbyl ether group, R ′ represents an aliphatic saturated hydrocarbyl group, Y represents a hydrolyzable organic group, and n represents 0 1 or 2. When there are a plurality of Ys,
They do not have to be the same. Specific examples of the unsaturated silane compound include those in which R is vinyl, allyl, etc., Y is methoxy, ethoxy, etc., and R'is methyl, ethyl, etc. A particularly preferred unsaturated silane compound is represented by the following formula. CH ₂ ═CHSi (OA) ₃ (where A is a hydrocarbyl group having 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms) The most preferred compound is vinyltrimethoxysilane, vinyltriethoxysilane or vinyltriacetoxysilane. is there. The copolymer used in the present invention has an unsaturated silane compound unit content of 0.5 to 10% by weight, preferably 0.5 to 5% by weight, particularly preferably 0.5 to 2% by weight. . Generally, a water-crosslinked product of a copolymer having a high unsaturated silane compound content is more excellent in mechanical strength and heat resistance, but if the content is excessively high, the tensile strength, the elongation and the heat fusion property are deteriorated. The content range of 0.5 to 10% by weight is determined from this point.

As the silanol condensation catalyst used in the present invention, dibutyltin dilaurate, dibutyltin dioctoate, lead naphthenate, metal carboxylic acid salts such as cobalt naphthenate, organic bases such as dibutylamine and pyridine,
Examples thereof include inorganic acids such as sulfuric acid and hydrochloric acid, and organic acids such as acetic acid, stearic acid and maleic acid. The amount of silanol condensation catalyst used is generally 0.00 based on the amount of copolymer in the composition.
It is 1 to 10% by weight, preferably 0.01 to 5% by weight, and particularly preferably 0.03 to 3% by weight.

The vinylidene fluoride rubber used in the present invention is a copolymer of vinylidene fluoride and propylene pentafluoride, a copolymer of vinylidene fluoride and propylene hexafluoride or vinylidene fluoride and 3 Examples thereof include a copolymer with fluorinated ethylene chloride, but in the present invention, a copolymer of vinylidene fluoride and propylene hexafluoride is particularly preferable. The amount of vinylidene fluoride rubber added is 0.015 to 0.5 part by weight, preferably 0.1.
025 to 0.3 parts by weight. When the amount of vinylidene fluoride rubber added is 0.015 parts by weight or less, the slipperiness is insufficient and it is not effective in preventing the generation of die scum, and even when added in an amount of 0.3 parts by weight or more, the effect reaches saturation. On the contrary, when 0.5 parts by weight or more is added, the compatibility is deteriorated and the surface is whitened. Vinylidene fluoride rubber is AST
The Mooney viscosity at 121 ° C. measured according to MD-1614 is 20 to 50 and is soluble in tetrahydrofuran, and the molecular weight measured by gel permeation chromatography is 30,000 to 70,000, and the Mooney viscosity is 20 or less or When the molecular weight is 30,000 or less, the lubricity is insufficient, and when the Mooney viscosity is 50 or more or the molecular weight is 70,000 or more, the compatibility with the polyolefin resin is poor. Particularly preferred are Mooney viscosities of 25-30 and molecular weights of 40,000-50,000.

[0008] The mechanism of the generation of the dicus is that when the mixture of the ethylene-unsaturated silane compound copolymer and the silanol condensation catalyst is extruded, the crosslinking gradually progresses in the extruder, the resin flow on the inner wall surface slows down, and It is considered that the cross-linked product adheres and accumulates, forms a die scatter with the extrusion-molded product, is extruded and accumulates in the front part of the die outlet, and is generated as a so-called eye die die scum. Although such a phenomenon cannot be excluded from speculation, when the resin passes through the inside of the extruder and the inside of the die, a thin film of the added vinylidene fluoride rubber is formed on the metal surface, and the surface of the film becomes slippery. It is considered that since the resin is rich, the resin is prevented from staying and the so-called die scum is prevented from being generated. Generally, a plastic composition has a very strong affinity for metals, and decomposed products and crosslinked products generated in the extruder or at a place where the inner wall of the die is likely to stay tend to be easily generated as die scum. However, a vinylidene fluoride-based rubber film with a high surface lubricity is formed on the metal surface, which reduces the affinity with the metal and improves the fluidity of the resin, allowing the resin to pass without staying inside the die. It is thought that the occurrence can be prevented.

The vinylidene fluoride rubber may be added at the time of producing the master batch of the silanol condensation catalyst, at the time of producing the ethylene-unsaturated silane compound copolymer, or at the ethylene-unsaturated silane compound. When the copolymer and the silanol condensation catalyst are mixed, the effect does not change even if they are added as a master batch of vinylidene fluoride rubber or vinylidene fluoride rubber having a high concentration in advance. The composition of the present invention may contain additives such as pigments and antioxidants, ultraviolet absorbers, flame retardants, and inorganic fillers for facilitating identification according to the purpose.

[0010]

【Example】

<< Production of Masterbatch of Silanol Condensation Catalyst >> Low-density polyethylene (PE) having a density of 0.922 and a melt flow of 1.5 was used as a base resin, and 100 parts by weight of the PE was used as a silanol condensation catalyst. Silanol containing vinylidene fluoride rubber of the following 10 types (CM1 to CM10), some of which have a high concentration A masterbatch of condensation catalyst was prepared. CM1: No other additives CM2: 2 parts by weight of stearic acid CM3: 10 parts by weight of polyethylene wax CM4: 20 parts by weight of silicone wax CM5: 20 parts by weight of silicone oil CM6: 0.2 parts by weight of vinylidene fluoride rubber CM7: Fluorine Vinylidene fluoride rubber 5 parts by weight CM8: Vinylidene fluoride rubber 0.4 parts by weight CM9: Vinylidene fluoride rubber 2 parts by weight CM10: Vinylidene fluoride rubber 3 parts by weight The vinylidene fluoride rubber used has a molecular weight of 45,000,
It is a copolymer of vinylidene fluoride having a Mooney viscosity of 28 and propylene hexafluoride.

<< Comparative Examples 1 to 7, Examples 1 to 3 >> Silanol condensation was carried out with respect to 95 parts by weight of an ethylene-unsaturated silane compound copolymer containing 1.5% by weight of an ethylenically unsaturated silane compound unit. 5 CM1-CM10 each as catalyst
Parts by weight were added, each was mixed with a mixer, extrusion-molded under the following conditions, and evaluated by the amount of die scud adhered to the front surface of the die. The results are shown in Table 1. Extruder: 50φ single screw extruder, L / D = 22, C.I. R = 3.5 Die: 12 φ tube die (chrome plating on the inner surface of the die) Temperature: C1 C2 C3 C4 D1 D2 (° C) 120 160 160 170 180 170 170 Discharge rate: 15 kg / hour (40 rpm) Ethylene-unsaturated silane compound The amount of vinylidene fluoride rubber added is 0.015 to 100 parts by weight of the copolymer.
In the case of the examples in the range of 0.2 parts by weight, all evaluation items are good. On the other hand, in Comparative Example 6 in which the amount of vinylidene fluoride-based rubber added was 0.015 parts by weight or less and other comparative examples in which no vinylidene fluoride-based rubber was added, the amount of die scum generated was large and the effect was poor. In Comparative Example 7 in which the amount of rubber added was 0.2 parts by weight or more, no die scum was generated, but the surface was whitened and the appearance was poor.

Example 4 5 parts by weight of CM1 as a silanol condensation catalyst was added to 95 parts by weight of an ethylene-unsaturated silane compound copolymer containing 1.5% by weight of an ethylenically unsaturated silane compound unit. 0.1 part by weight of the same vinylidene fluoride rubber as that used above was mixed and evaluated in the same manner as above, and the results are shown in Table 1. Good results were obtained without the occurrence of die scum. Example 5 Using the same material as the masterbatch of silanol condensation catalyst, 10 parts by weight of vinylidene fluoride rubber and various additives were mixed with 100 parts by weight of PE, and the mixture was stirred with a mixer, and then Banbury. Knead and granulate with a mixer,
A master batch of vinylidene fluoride rubber was produced.
5 parts by weight of CM1 as a silanol condensation catalyst and 95 parts by weight of an ethylene-unsaturated silane compound copolymer having an ethylenically unsaturated silane compound unit content of 1.5% by weight, and the vinylidene fluoride-based system prepared above 1 part by weight of a rubber masterbatch was mixed and evaluated in the same manner as above.
The results are shown in Table 1. Good results were obtained without the occurrence of die scum.

[0013]

[Table 1]

[0014]

EFFECTS OF THE INVENTION The crosslinkable polyolefin resin composition of the present invention does not generate the die scus which is usually generated during extrusion molding, and thus does not require a special device or a special method for removing the die scum, and has a characteristic property. In addition, it is excellent in continuous productivity and has a high economic efficiency that has brought about significant cost reduction and process rationalization.

Claims (3)

[Claims] 1. A copolymer of ethylene and an ethylenically unsaturated silane compound, wherein the content of the ethylenically unsaturated silane compound unit is 0.5 to 10% by weight, and silanol condensation. A polyolefin resin composition comprising 0.015 to 0.2 parts by weight of vinylidene fluoride rubber based on 100 parts by weight of a catalyst. 2. A vinylidene fluoride rubber is a copolymer of vinylidene fluoride and propylene pentafluoride, a copolymer of vinylidene fluoride and propylene hexafluoride, or vinylidene fluoride and ethylene trifluoride chloride. The polyolefin resin composition according to claim 1, which is a copolymer. 3. A vinylidene fluoride rubber is ASTM-D.
The polyolefin resin composition according to claim 1 or 2, wherein the Mooney viscosity at 121 ° C measured according to -1614 is 20 to 50 and the molecular weight measured by gel permeation chromatography is 30,000 to 70,000 dissolved in tetrahydrofuran. object.