JP2014156570A - Production method of silane cross-linked resin molding and molding using the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of a polyolefin-based silane cross-linked resin molding and a molding using the method, which solve the problems that a graft reaction step is necessary by which an alkoxysilane which crosslinks with water is introduced in a polyolefin-based resin, that a large-sized facility is necessary for stirring and mixing, and that, when an economical film grade low density polyethylene (PE) and linear low density PE is used, surface smoothness becomes deteriorated.SOLUTION: To provide a silane cross-linked polyolefin resin molding obtained by a production method comprising: planning a combination of polyolefin-based resin components containing an alkoxysilane compound having an unsaturated double bond, a radical generator, a silanol condensing catalyst, and an antioxidant and comprising a PE-based resin and a polypropylene-based resin; dividing these into 3 constituent components which are mixed respectively; transferring these into an extruder to be molded; and thereafter reacting the molding with moisture.

Description

  The present invention relates to a method for producing a polyolefin-based silane cross-linked resin molded body having moldability and economy, and a molded body using the same.

  Needless to say, electric wires and cables are used as a power transport medium, but the amount of use in the field of information transmission has increased due to the development of an information-oriented society and the use of electronics for all types of equipment. For this reason, except for special cases, the covering materials for electric wires and cables, which are mostly made of plastic materials, also play an important role, and are the original purpose of electric wires and cables: electrical insulation, protection, ease of handling, and safety. In addition to the above, aesthetics, economic efficiency, environmental friendliness, etc. have been demanded.

  Power transmission media include transmission lines that send electricity generated at power stations to substations in the areas where they are consumed, distribution lines that distribute electricity that has been reduced to a predetermined voltage at substations to factories, buildings, and homes. It can be divided into wiring used in buildings and homes, and electric wires for special equipment used in ships, aircraft, automobiles, etc.

  High-voltage power transmission / distribution devices have a somewhat complicated covering structure, but underground transmissions use cross-linked PE with excellent electrical properties and mechanical strength as the inner insulator, and the outer sheath As polyvinyl chloride (PVC) or PE. Some of the inner cross-linked PEs may be applied with electron beam cross-linking that irradiates an electron beam or chemical cross-linking using a peroxide, but can be cross-linked by contact with moisture in the presence of a silanol condensation catalyst. Often water cross-linked PE is used.

  For power cords such as home appliances and OA equipment, thermoplastic elastomer (TPE) is often used for reasons such as good moldability, but in the case of electric wires used in high temperatures, the coating is made of polyethylene terephthalate. In addition to (PET) film, crosslinked PE is also used. Water-crosslinked PE is often applied to this crosslinked PE.

  On the other hand, as an information transmission medium, a connecting wire between electronic devices in offices and homes, particularly a TV lead wire, etc., uses PE coating or rubber for its outer sheath. The type PE is often used.

  In recent years, the use of electric wires in automobiles has increased due to the progress of electronics and hybridization. The main coating material is PVC, but PET or water-crosslinking PE is used as a coating material that requires heat resistance.

  Thus, water cross-linked PE is now an indispensable insulating material. In the future, it is expected that it will be used in place of PVC containing chlorine from the viewpoint of environmental properties, and it will be used in place of expensive PET from the viewpoint of economy.

  As such a water-crosslinked PE, any of high-density PE (HDPE), linear low-density PE (LLDPE), and low-density PE (LDPE) can be used. . HDPE is a linear polymer with no branching, so it has a high degree of crystallinity and is most excellent in electrical, mechanical, thermal, and chemical properties required for wire coating materials. However, there is a problem of surface smoothness called melt fracture in which irregularities are formed on the surface by extrusion molding. This is a peculiar swelling phenomenon seen in the case of pore extrusion such as wire coating processing, and is presumed to be due to the Balas effect (see Non-Patent Document 1). Since LDPE is a branched polymer having long branches, it has a low crystallinity, is easy to mold and is excellent in flexibility, but has poor tensile strength, heat resistance, etc. . LLDPE is a linear polymer having a short branch and exists in the middle of HDPE and LDPE due to its structure, but has the problem of surface smoothness like HDPE.

  However, LLDPE produced by copolymerization of ethylene and α-olefin is superior to LDPE in mechanical strength, heat resistance, and hot sealability, seal strength, impact resistance, hot tack, etc. However, since it surpasses Surlyn (registered trademark: PE ionomer), the conventional LDPE has been replaced by LLDPE, mainly in packaging materials, and a great advantage has been obtained in terms of economy. Therefore, in the field where economical efficiency is required such as coated electric wires, from the viewpoint of raw material price, PE for film that is used in large quantities as packaging materials, that is, LDPE or LLDPE having a low melt flow ratio (MFR), In particular, it has become necessary to make full use of LLDPE as a water-crosslinking PE.

  Therefore, in order to solve the above-described problem of formability (surface smoothness), they are disclosed in JP-A-55-128441, JP-A-60-139713, JP-A-9-306241, and the like. Although such improvements have been made, the following problems remain.

  A problem common to the prior art is that a water-crosslinked PE for crosslinking with moisture in the presence of a silanol condensation catalyst is prepared in advance. That is, under the radical generator, PE and an alkoxysilane compound having an unsaturated double bond are heated, and a graft reaction step is required to introduce the alkoxysilane into the PE molecule by a radical reaction, resulting in poor productivity. There's a problem. Further, since this process is performed using a large amount of resin, a large-sized heating and mixing apparatus is required, and there is a problem that the process time is long. For example, Japanese Patent Application Laid-Open No. 55-128441 improves the problem of surface smoothness by introducing polypropylene into LDPE having an MFR of 2.0, but requires a graft reaction step.

  On the other hand, the problem of surface smoothness has not been solved yet. JP-A-60-139713 improves the moldability of LLDPE, but does not mention surface smoothness. Furthermore, Japanese Patent Laid-Open No. 9-306241 discloses an improvement in surface smoothness at a coated wire production speed of 40 m / min or less, but the effect in practical high-line production at which problems occur is unconfirmed.

  As described above, the conventional method for producing a silane-crosslinked molded article using water-crosslinked PE can reduce the raw material price, but simultaneously solves the problems of moldability (surface smoothness) and productivity (economical efficiency). It is difficult to do so.

JP-A-55-128441 JP-A-60-139713 JP-A-9-306241 JP-A-10-120797

Yasushi Oyanagi, Engineering Plastics-Characteristics and Processing-, p.74, 1985.

  The present invention relates to a method for producing a silane-crosslinked resin molded body having an inexpensive PE-based resin for film and having moldability and economic properties in addition to electrical, mechanical, thermal, and chemical properties. And the objective is to provide the molded object using the method. In particular, an object of the present invention is to provide a method for producing an electric wire / cable coated with a polyolefin-based silane cross-linked resin and a covered electric wire / cable using the method.

  It has been found that the above problem can be solved by applying the following manufacturing method. That is, the present invention includes 0 to 92 parts by mass of a polyolefin resin component (A) including at least one PE resin, an organic alkoxysilane compound (1) having an unsaturated double bond, and a radical generator (2). 5 to 97 parts by mass of a polyolefin resin component (B-1 · 2) containing at least one PE resin and a polyolefin resin component (C-) containing a silanol condensation catalyst (3) and an antioxidant (4) 3 · 4) 3 to 30 parts by mass are prepared as master batches, and after mixing (A), (B-1 · 2), and (C-3.4), or after each A method for producing a crosslinked formed article, wherein the components are independently supplied to an extruder, reacted while being melt kneaded, extruded, contacted with moisture, and crosslinked. As a result, it became possible to produce a silane cross-linked resin molded article excellent in physical properties, surface smoothness and economy, particularly a coated electric wire / cable, using the production method.

  Further, among 100 parts by mass of the total resin components (ABC-1, 2 and 3) of the resin components (A), (B-1 and 2) and (C-3.4), a polypropylene (PP) type Silane, wherein 30 to 2 parts by mass of resin component (p) is contained in at least one component of (A), (B-1 · 2), and (C-3.4) It is a manufacturing method of a crosslinked resin molded body, and is a silane crosslinked resin molded body using the manufacturing method.

  More preferably, the total resin component (ABC-p) of the resin components (Ap), (Bp · 1 · 2), and (Cp · 3 · 4) containing the PP resin (p). 1 · 2, 3 · 4) A method for producing a silane-crosslinked resin molded product comprising a dissimilar PE-based resin in 100 parts by mass, wherein the compounding ratio is 10 to 30 parts by mass, It is a silane cross-linked resin molding using the production method.

  More preferably, the total resin component (ABC) of the resin component (Ap), (Bp · 1 · 2), and (Cp · 3 · 4) containing the PP resin component (p). -P · 1, · 2 · 3 · 4) containing 100 parts by mass of a PE-based resin called an ethylene-α-olefin copolymer called a thermoplastic rubber (TPE) having a melting point of 40 to 80 ° C. It is a manufacturing method of the crosslinked molded object characterized by the compounding quantity being 5-15 mass parts, It is a silane crosslinked molded object using the manufacturing method.

  The TPE is originally a PE-based rubber of an ethylene-α-olefin copolymer, and is distinguished from a PE-based resin. However, in the present specification, it is treated as a PE-based resin.

  However, the alkoxysilane compound (1), the radical generator (2), the silanol condensation catalyst (3), and the antioxidant (4) are used with respect to 100 parts by mass of the total resin component (ABC). 1) 0.2-4.0 parts by mass, radical generator (2) 0.05-0.4 parts by mass, silanol condensation catalyst (3) 0.005-0.04 parts by mass, and antioxidant ( 4) 0.05-0.5 mass part is contained in (B) and (C), respectively.

  By using the production method of the present invention, in addition to electrical, mechanical, thermal, and chemical properties, a silane cross-linked resin molded article having moldability and economy, in particular, a coated wire of polyolefin-based silane cross-linked resin A cable is obtained by extrusion.

  The production method of the present invention eliminates the need for a conventional graft reaction step of introducing an alkoxysilane for crosslinking with water into a polyolefin resin, the polyolefin resin component (A) containing at least a PE resin, A polyolefin resin component (B-1 · 2) containing an organic alkoxysilane compound having a heavy bond and a radical generator, and containing at least a PE resin, and a polyolefin resin component (C) containing a silanol condensation catalyst and an antioxidant. It has a great feature in that three types of master batches -3.4) are prepared in advance. On the other hand, as raw materials, the polyolefin resin contains a PP resin component, the polyolefin resin is one or two PE resins, and the polyolefin resin contains a PE resin called TPE. It is characterized by.

  Although it is clear that omission of the graft reaction step increases the production efficiency, the production of the above three master batches is also an important technique for improving the productivity. First, the amount of resin mixed and dispersed in the resin, such as the alkoxysilane compound, radical generator, silanol condensation catalyst, and antioxidant, can be freely adjusted (reduced), downsizing the equipment, and shortening the process time. Can be realized. In addition, a large-sized agitating mixer is not required by feeding the extruder independently from the three master batches.

Although the example of the method of manufacturing the resin composition of this invention which has such a characteristic is demonstrated concretely next, it is not limited to this. Here, in order to clarify the presence or absence of the PE-based resin component and the PP-based resin, the description will be made using the PE-based resin (e) regardless of the type.
(A) As a polyolefin resin component (B) containing at least one PE resin (e), at least one PE resin (e), an alkoxysilane compound (1), and a radical generator (2) A fixed amount is stirred and mixed with a Henschel mixer to prepare a masterbatch (Be · 1 · 2). Next, as the polyolefin resin component (C), a predetermined amount of a silanol condensation catalyst (3) and an antioxidant (4) are added to the PP resin component (p), and after heating and kneading by using a Banbury mixer, pellets A master batch (Cp · 3 · 4) is prepared. These (Be · 1 · 2) and (Cp · 3 · 4) can be stirred and mixed with a tumbler to produce the resin composition of the present invention.
(B) As a polyolefin resin component (A) containing at least one PE resin (e), pellets of at least one PE resin (e) are directly prepared as a master batch (Ae). Next, as a polyolefin resin component (B) containing at least one PE resin, pellets of the same or different PE resin (e) as the PE resin (e) contained in the polyolefin resin component (A) are used. A master batch in which residual heat is applied so that the temperature is lower by about 10 ° C. than the melting point of the PE resin (e), and a predetermined amount of the alkoxysilane compound (1) and the radical generator (2) are impregnated with a Henschel mixer ( (Be · 1 · 2) is prepared. Next, as the polyolefin resin component (C), a predetermined amount of a silanol condensation catalyst (3) and an antioxidant (4) are added to the PP resin component (p), and after heating and kneading by using a Banbury mixer, pellets A master batch (Cp · 3 · 4) is prepared. These (Ae), (Be · 1 · 2), and (Cp · 3 · 4) can be stirred and mixed with a tumbler to produce the resin composition of the present invention. However, if the polyolefin resin component (B) is less than 25%, preheating and impregnation are unnecessary.
(C) As the polyolefin resin component (B) containing at least one PE resin (e), at least one PE resin (e), the alkoxysilane compound (1), and the radical generator (2) A fixed amount is stirred and mixed with a Henschel mixer to prepare a masterbatch (Be · 1 · 2). Next, as the polyolefin resin component (C), a PE resin (e) that is the same or different from the PE resin (e) constituting the polyolefin resin component (B) and a PP resin component (p) are mixed. Then, a predetermined amount of the silanol condensation catalyst (3) and the antioxidant (4) are added, and after heating and kneading by using a Banbury mixer, a pelletized master batch (Ce · p · 3 · 4) is produced. . These (Be · 1 · 2) and (Ce · p · 3 · 4) can be stirred and mixed with a tumbler to prepare the resin composition of the present invention.
(D) As a polyolefin resin component (B) containing at least one PE resin (e), a predetermined amount of at least one PE resin (e) and a PP resin component (p) pellets and an alkoxysilane compound (1) and radical generator (2) are stirred and mixed with a Henschel mixer to prepare a masterbatch (Be · p · 1 · 2). Next, as the polyolefin resin component (C), a predetermined amount of silanol condensation catalyst (3) is added to the same or different PE resin (e) as the PE resin (e) constituting the polyolefin resin component (B). ) And an antioxidant (4), and a heat-kneaded by using a Banbury mixer, and then a pelletized masterbatch (Ce 3.4) is prepared. These (Be · p · 1 · 2) and (Ce · 3 · 4) can be stirred and mixed with a tumbler to prepare the resin composition of the present invention.
(E) As a polyolefin resin component (A) containing at least one PE resin (e), a master batch in which pellets of at least one PE resin (e) and a PP resin component (p) are stirred and mixed with a tumbler. Prepare (Ae · p). As a polyolefin resin component (B) containing at least one PE resin (e), pellets of the same or different PE resin (e) as the PE resin (e) constituting the polyolefin resin component (A) The master batch (Be · 1 ·) is heated to a temperature lower than its melting point by about 10 ° C. and impregnated with a predetermined amount of alkoxysilane compound (1) and radical generator (2) with a Henschel mixer. 2) is prepared. Next, as the polyolefin resin component (C), a predetermined amount of silanol condensation catalyst (3) and oxidation are applied to the same or different PE resin as the PE resin (e) constituting the polyolefin resin component (A). The inhibitor (4) is added, and after heating and kneading by using a Banbury mixer, a pelletized masterbatch (Ce 3.4) is prepared. These (Ae · p), (Be · 1 · 2), and (Ce · 3 · 4) can be stirred and mixed with a tumbler to produce the resin composition of the present invention. . However, if the polyolefin resin component (B) is less than 25%, preheating and impregnation are unnecessary.
(F) As a polyolefin resin component (A) containing at least one PE resin (e), pellets of at least one PE resin (e) are directly prepared as a master batch (Ae). As the polyolefin resin component (B) containing at least one PE resin (e), the PE resin (e) constituting the polyolefin resin component (A) is different from or the same type of PE resin (e) and PP. A predetermined amount of alkoxysilane compound (1) and radical generator (2) are stirred and mixed with a Henschel mixer into pellets of the resin-based resin component (p) to prepare a master batch (Be · p · 1 · 2). . Next, as the polyolefin resin component (C), a predetermined amount of silanol condensation catalyst (3) is added to the same or different PE resin (e) as the PE resin (e) constituting the polyolefin resin component (A). ) And an antioxidant (4), and a heat-kneaded by using a Banbury mixer, and then a pelletized masterbatch (Ce 3.4) is prepared. These (Ae), (Be · p · 1, 2), and (Ce · 3 · 4) can be stirred and mixed with a tumbler to produce the resin composition of the present invention. .

  In order to clarify the example of the above production method, it is summarized in Table 1.

  Specific examples of the production method have been described above, and production methods represented by production methods (b), (e), and (f) are particularly preferable. In the production methods (A), (C), and (D), a large-scale mixing is required to stir and mix the polyolefin resin (B), the alkoxysilane compound (1), and the radical generator (2). In the manufacturing methods (b), (e), and (f), the amount of resin to be handled is greatly reduced, and the kneading machine is reduced in size, space and energy. This is because it becomes possible.

  The resin composition thus produced is fed into an extruder and molded, and then brought into contact with moisture to complete the crosslinking reaction, whereby the silane crosslinked resin molded article of the present invention is produced.

  The resin composition to the extrusion molding machine may be sent in a batch from one hopper, but the final stirring and mixing of each master batch is omitted, and each master batch is installed with a plurality of hoppers. You may send each to an extrusion machine independently.

  As the extrusion molding machine, a general one can be used, and it is necessary to set optimum conditions depending on the model of the apparatus. This condition is determined by evaluation of physical properties and gel fraction.

  In the case of manufacturing a covered wire / cable, the extruded resin is almost uniformly coated on the conductor through a molding die in the crosshead at the tip. There is no restriction | limiting in a conductor, It can use also for manufacture of not only the insulator of a covered wire but a sheath.

  In the cross-linking step, conditions according to the product to be manufactured are set, but in this case as well, it is determined by evaluating physical properties and gel fraction.

  The silane cross-linked resin molded product is extruded from the head while the radical reaction and the ionic reaction proceed simultaneously in the process of being extruded by the screw inside the heated cylinder, but mainly the radical reaction proceeds preferentially, The production is completed by a crosslinking reaction with moisture. As described in detail later, the grafting process can be omitted by only once history of the extrusion molding machine. As will be described in detail later, the decrease in the viscosity of the resin composition increases the mobility of radicals and facilitates the reaction. I guess that is because it became.

  On the other hand, the PE-based resin component (e) used in the present invention is an inexpensive PE-based resin for film, that is, an MFR of 0. It is preferable to use a high pressure process LDPE or various LLDPEs of 5 or more and 5 or less. In particular, as a coating material for electric wires and cables, LLDPE is preferable from the viewpoint of achieving both physical properties and economical efficiency.

  LLDPE includes various LLDPEs such as a gas phase polymerization method and a solution polymerization method, and an ethylene-α-olefin copolymer of a solution polymerization method is preferable. Specifically, an ethylene-butene copolymer, an ethylene-hexene copolymer, and an ethylene-octene copolymer can be used.

  Examples of such inexpensive LLDPE for film market distribution are as follows. For example, commercially available gas phase polymerization method LLDPE includes Novatec (registered trademark) LL and Novatec (registered trademark) C6 for films made by Nippon Polyethylene. Furthermore, as a commercially available solution polymerization method LLDPE, there are Neozex (registered trademark), Ultozex (registered trademark), Moretec (registered trademark), Evolue (registered trademark), etc. manufactured by Prime Polymer Co., Ltd.

  Instead of using PE resins (e) such as high-pressure LDPE and various LLDPE used for film applications where the MFR is 0.5 or more and 5 or less, two kinds of ethylene-α-olefins are used. A copolymer can also be mixed and used. Specifically, it is selected from an ethylene-butene copolymer, an ethylene-hexene copolymer, and an ethylene-octene copolymer. In particular, one kind of LLDPE has a melting point of 100 ° C. or less. As the combination, an ethylene-hexene copolymer and an ethylene-octene copolymer are suitable. The dissimilar PE resin component is preferably contained in an amount of 10 to 30 parts by mass out of 100 parts by mass of the total polyolefin resin component, and when outside this range, there is no effect of improving the surface smoothness. In addition, the use of LLDPE having a melting point of 100 ° C. or lower is because the evaporation can be suppressed when the alkoxysilane compound (1) is impregnated as in the production methods (b) and (e). There are also advantages.

  In addition, PE-based resins such as high-pressure LDPE and various LLDPE used for film applications having an MFR of 0.5 or more and 5 or less are called thermoplastic elastomers (TPE) and have an melting point of 40 to 80 ° C. -A PE-based resin that is an olefin copolymer may be mixed and used. It is preferable that 5-15 mass parts of TPE is contained among the total polyolefin resin components. When the amount is less than 5 parts by mass, there is no effect of improving the surface smoothness, and when it is 15 parts by mass or more, the thermal and mechanical properties are deteriorated. In addition, the use of TPE having a low melting point also has an effect on the production process that evaporation can be suppressed when impregnated with the alkoxysilane compound (1), as in the case of LLDPE having a low melting point. As a resin that performs the same function as TPE, ethylene-ethyl acrylate (EEA) resin, ethylene-butyl acrylate (EBA) resin, and ethylene-vinyl acetate (EVA) resin can be applied. 9% or more EEA resin and EVA resin having a VA content of 9% or more are particularly preferred. For example, TPE is Dow Engage etc., EEA and EBA resin are DuPont Elvalloy (registered trademark), Nippon Unicar EEA etc., EVA resin is Nippon Polyethylene Novatec (registered trademark) EVA, Evaflex (registered trademark) manufactured by Mitsui / DuPont Polychemical Co., Ltd. and Nippon Unicar Co., Ltd. are commercially available.

  The PP resin component (p) of the present invention includes a homopolymer (h-PP) of a PP homopolymer, a random PP (r-PP) that is a copolymer with a small amount of ethylene and / or 1-butene, Any of block PP in which the rubber component is dispersed in h-PP or r-PP can be used, and it is preferable to use 30 to 2 parts by mass of the total polyolefin resin component. When the amount is less than 2 parts by mass, there is no effect of improving moldability, and when the amount is 30 parts by mass or more, the thermal characteristics are deteriorated.

  In particular, r-PP is preferred as the PP resin component (B) of the present invention. Further, r-PP having an MFR of 8 or more is preferable, but 15 or more is more preferable, and 25 or more is even more preferable.

  For example, as marketed products of such PP-based resins, Novatec (registered trademark) PP manufactured by Nippon Polypropylene, Polypropylene Sun Allomer manufactured by Sun Allomer, Sumitomo Noblen (registered trademark) manufactured by Sumitomo Chemical Co., Ltd. and Prime Poly Pro manufactured by Prime Polymer Co., Ltd. There are products such as (registered trademark).

  Examples of the organic alkoxysilane compound (1) having an unsaturated double bond that can be preferably used in the present invention include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltributoxysilane, vinyldimethoxyethoxysilane, and vinyldimethoxybutoxy. Examples include silane, vinyldiethoxybutoxysilane, allyltrimethoxysilane, and allyltriethoxysilane.

  The radical generator (2) used in the present invention is preferably an organic peroxide. For example, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane, 2,5-dimethyl-2,5-di (tert- Butylperoxy) hexyne-3, 1,3-bis (tert-butylperoxyisopropyl) benzene, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, n-butyl-4 4-bis (tert-butylperoxy) valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tert-butylperoxybenzoate, tert-butylperoxyisopropyl carbonate, diacetyl peroxide Lauroyl peroxide , And it may be mentioned tert- butyl cumyl peroxide and the like. Of these, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane, and 2,5-dimethyl-2,5- Most preferred is di- (tert-butylperoxy) hexyne-3.

  Examples of the silanol condensation catalyst (3) that can be used in the present invention include dibutyltin dilaurate, dibutyltin dioctate, dibutyltin diacetate, dioctyltin dilaurate, zinc stearate, lead stearate, barium stearate, Examples include calcium stearate, sodium stearate, lead naphthenate, lead sulfate, zinc sulfate, and organic platinum compounds.

  Examples of the antioxidant (4) that can be used in the present invention include 4,4′-dioctyl diphenylamine, N, N′-diphenyl-p-phenylenediamine, and 2,2,4-trimethyl-1 , 2-dihydroquinoline polymers such as amine antioxidants, pentaerythritol-tetrakis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate), octadecyl-3- (3,5 -Di-tert-butyl-4-hydroxyphenyl) propionate and 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene Phenolic antioxidants, bis (2-methyl-4- (3-n-alkylthiopropionyloxy) -5-tert-butylphenyl) sulfide, 2-mer Script benzimidazole and zinc salts, and, pentaerythritol - tetrakis (3-lauryl - thiopropionate) sulfur-based antioxidants such as and the like. In particular, a findnt phenolic antioxidant is preferred, and specific examples include pentaerythritol-tetrakis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate).

  In the present invention, in addition to the above components, a metal deactivator, weathering agent, lubricant, colorant, or other additive can be appropriately blended within a range not impairing the object of the present invention.

  Metal deactivators include N, N′-bis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyl) hydrazine, 3- (N-salicyloyl) amino-1,2,4. -Triazole, 2,2′-oxamidobis- (ethyl 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate) and the like.

  Examples of the weathering agent include general weathering agents such as a light stabilizer (for example, a hindered amine-based light stabilizer) or an ultraviolet absorber (for example, a benzotriazole-based ultraviolet absorber, carbon black).

  Examples of the lubricant include hydrocarbons, fatty acids, fatty acid amides, esters, alcohols, metal soaps, silicones, and the like, and hydrocarbons and silicones are particularly preferable.

  By the way, conventionally, it is necessary to previously produce a polyolefin resin having an alkoxysilane in a side chain by a radical reaction between a polyolefin resin and an organic alkoxysilane compound having an unsaturated double bond, using a radical generator. It has been reported. However, in the production method of the present invention, the graft reaction step can be eliminated. The reason for this is not clear, but it is estimated as follows.

  That is, a change occurred in the viscoelastic behavior caused by the optimum combination of a polyolefin resin component and a PP resin component containing at least one PE resin used for film applications having an MFR of 0.5 or more and 5 or less. That is. It is considered that the viscosity in the extruder decreased, the mobility of radicals increased, and the graft reaction of the organoalkoxysilane compound having an unsaturated double bond due to the radical reaction to the polyolefin resin was sufficiently caused. This change in viscoelastic behavior also acted effectively as an effect of improving the surface smoothness.

  The factor that improved the surface smoothness is considered as follows. The unevenness of the surface of the extrusion molded body rises due to the normal stress effect peculiar to the viscoelastic body when the resin melted in the extrusion machine goes out to the outside from the nozzle, and the shape becomes solid from the melt. It is presumed that this was also left behind. Based on this, like a linear molecule or a polymer having a narrow molecular weight distribution, it is easier to crystallize and the higher the coagulation rate, the easier it is to form irregularities in the order of LDPE, LLDPE, HDPE. Has been reported. In particular, the Balas effect (see Non-Patent Document 1), which is a peculiar swelling phenomenon seen in the case of pore extrusion as in the case of wire coating in extrusion molding, becomes more prominent as high-speed molding is performed. It seems to come. Therefore, it is considered that the solidification rate is reduced and the surface smoothness is improved by using a polyolefin resin containing different types of PE resin or mixing a PP resin component.

  Furthermore, PE-type resin which is two kinds of ethylene-α-olefin copolymer is mixed, or PE-type resin called TPE with melting point of 40-80 ° C is mixed. It was also found that the viscoelastic behavior was changed more optimally.

  Hereinafter, although it demonstrates in detail based on an Example, this invention is not limited to these.

[sample]
The PE resin, PP resin, organic alkoxysilane compound having an unsaturated double bond, radical generator, silanol condensation catalyst, and antioxidant used in this example are shown in Table 2.

[Mixing method]
The resin pellets were mixed using a tumbler and stirred at room temperature for 10 minutes.
In order to impregnate the resin pellet with the organoalkoxysilane compound and the radical generator, in the case of Examples 12, 13, 27, and 28, a Henschel mixer is used so that the temperature is 10 ° C. lower than the melting point of the resin. Is heated and stirred for 3 minutes. In other embodiments, it is only stirred for 3 minutes in a Henschel mixer.
When the resin, the silanol condensation catalyst and the antioxidant were mixed, they were kneaded at 200 ° C. for 5 minutes and pelletized using a Banbury mixer.

[Wire production process]
The extrusion machine uses a cylinder having a diameter of 70 mm and L / D = 25. The extrusion temperature is set to cylinder: 190 ° C., flange: 200 ° C., head: 210 ° C., die: 220 ° C. The conductor was coated with resin at 100 and 150 m / min. The conductor was a 1 / 0.8 A annealed copper wire, the thickness of the coating resin was 0.4 mm, and the outer shape was about φ1.6 mm.

[Crosslinking process]
It was immersed in 60 degreeC warm water for 24 hours.

[Evaluation]
○ Heat deformation: Based on JIS-C3005, the test was performed at a test temperature of 120 ° C. and a load of 5N.
○ Hot set: Based on JIS-C3660-2-1, the test temperature is 200 ° C., the load is 20 N / mm ² , the load time is 15 minutes, the elongation during heating is 100% or less, and the permanent elongation after cooling is 25%. The following were marked with ◯, the others were marked with x, and ◯ were marked as acceptable.
○ High line speed manufacturability: The appearance of each line speed was confirmed. A product having a very good external appearance was evaluated as ◯, a product having no problem, a product having a slightly poor external appearance was evaluated as Δ, a product having a problem in product was evaluated as ×, and a product having a linear speed of 100 m / min was evaluated as acceptable.
○ Low-temperature property A (low-temperature winding property): Based on JIS-C3005, after winding around a winding mandrel at a test temperature of −45 ° C., ○ was marked with no cracks, and the others were marked with ×. Although this test was not an essential condition depending on the application, it was a reference test irrelevant to pass / fail, but it was carried out to compare the properties with conventional silane cross-linked resin moldings.
O Low temperature B (cold resistance): Based on JIS-C3005, the test temperature was -65 ° C. As the sample, a sheet having a thickness of 2 mm produced under the same equipment and extrusion conditions as the electric wire was used. After the test, visual evaluation was performed, and a case where there was no change was indicated as ◯, a case where a pinhole was observed was indicated as △, and a case where there was a crack, a crack or the like was indicated as ×. Although this test was not an essential condition, it was a reference test that was unrelated to pass / fail, but it was carried out for comparison of characteristics with a conventional silane cross-linked resin molded product.

  Tables 3 and 4 show the results of producing a resin composition by the method shown in Production Method (A) and evaluating the products produced through the above [Electric Wire Production Process] and [Crosslinking Process].

  As is clear from Examples 1 to 6, Examples 16 to 21 and Comparative Examples 1 to 7, PP-based resins obtained good results in the range of 2 to 30 parts by weight regardless of the production method.

  From Examples 11 and 26 and Comparative Example 2, the antioxidant is preferably in the range of 0.05 to 0.5 parts by mass in order to impair the physical properties of the crosslinker.

  From Examples 3 and 18, Examples 7 to 10, and Examples 22 to 25, regardless of the production method, the type of PP-based resin is not practically questioned, but from the viewpoint of surface smoothness, r-PP Based resins are preferred. Further, even in the r-PP resin, as the MFR is larger, the smoothness is improved, and it is preferably 5 or more, more preferably 8 or more, and most preferably 25 or more.

  As can be seen from Examples 12 to 14 and 27 to 29, regardless of the production method, even when different types of PE-based resins or PE-based resins are mixed with TPE that is rubbery and has a very low density and melting point, Although not expressed in the experimental results, the surface smoothness was particularly excellent.

  As described above, it is extremely important in the production process that no change is observed in the physical properties and surface smoothness of the silane-crosslinked resin-formed product depending on the blending ratio of the resin composition regardless of the production method. That is, in the production methods (a), (c), and (d), a large mixer is required to impregnate the alkoxysilane compound (1) and the radical generator (2), and the process time However, in the manufacturing methods (b), (e) and (f), the amount of resin to be handled is greatly reduced, thereby reducing the size of the mixture and saving energy. It becomes possible.

  According to the method for producing a silane-crosslinked resin formed body of the present invention, a reaction step for grafting an alkoxysilane compound to a polyolefin resin is unnecessary, and it is possible to reduce the size of the apparatus and shorten the process, and to reduce the raw material cost. Since low LLDPE is used as a main component, it is excellent in productivity and economy. In addition, a molded article having excellent surface smoothness can be obtained in spite of using LLDPE having excellent electrical, mechanical, thermal and chemical properties as a main component. Therefore, it is particularly suitable for coated electric wires and cables, but can be widely applied to the production of cables, optical cords, power plugs, connectors, sleeves, boxes, tapes, tubes, sheets, and the like.

Claims (3)

0 to 92 parts by mass of a polyolefin resin component (A) containing at least one polyethylene (PE) resin, an organic alkoxysilane compound (1) having an unsaturated double bond, and a radical generator (2), and at least one kind 5 to 97 parts by mass of a polyolefin resin component (B-1 · 2) containing a PE resin and a polyolefin resin component (C-3-4) containing a silanol condensation catalyst (3) and an antioxidant (4) ) 3 to 30 parts by mass of each as a master batch, and after mixing (A), (B-1 · 2), and (C-3.4), or each component A method for producing a silane-crosslinked resin molded article, comprising: independently feeding to an extruder, reacting while melt kneading, extrusion molding, and then contacting with moisture. Polypropylene resin components (A), (B-1.2), and (C-3.4), 100 parts by mass of the total resin components (ABC-1, 2, 3, 4), polypropylene (PP) 30 to 2 parts by mass of a resin component (p) is contained in at least one component of (A), (B-1 • 2), and (C-3.4) The manufacturing method of the silane crosslinked resin molding of Claim 1. A silane cross-linked resin molded article obtained by the production method according to claim 1.