Resin composition, crosslinked resin composition, molded article, wire coating material, and wire

Abstract

To provide a resin composition, a crosslinked resin composition, a molded body, an electric wire coat material and an electric wire that have heat resistance, mechanical property and flame retardancy and are excellent in appearance.SOLUTION: Provided are a resin composition that contains the following (A), (B), (C), and (D); and a crosslinked resin composition that is obtained by cross-linking the resin composition, a molded body in which the crosslinked resin composition is used, an electric wire coat material that is made of the molded body, and an electric wire that is coated with the electric wire coat material. (A): a modified polyolefin that is graft-modified with unsaturated silane compound. (B): a metal hydroxide. (C): a crosslink catalyst. (D): a zeolite and / or calcium oxide.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a resin composition, a crosslinked resin composition, a molded article, an electric wire coating material, and an electric wire. More specifically, the present invention relates to a resin composition and a crosslinked resin composition that are optimal as coating materials for insulating electric wires that require high heat resistance, a molded article and an electric wire coating material obtained therefrom, and an electric wire coated with the electric wire coating material.

Background Art

[0002] In fields such as electric wire coatings, tubes, building materials, and automotive parts, high heat resistance is often required. Therefore, in order to improve heat resistance, the resin composition used for molding is crosslinked by a crosslinking method such as an electron beam irradiation crosslinking method, a chemical crosslinking method, or a water crosslinking method. Among them, the manufacturing method of a crosslinked resin composition obtained by water-crosslinking a resin composition has advantages in terms of manufacturing cost compared to other electron beam irradiation crosslinking methods and chemical crosslinking methods. Therefore, many studies on polyolefin-based resin compositions suitable for water crosslinking have been reported.

[0003] Generally, a crosslinked olefin-based resin composition by the water crosslinking method is obtained by graft reacting a polyolefin-based resin by adding a free radical generator such as dicumyl peroxide and a silane compound such as vinyltrimethoxysilane and melt kneading, and then blending a silanol condensation catalyst such as dioctyltin dilaurate and performing heat molding (extrusion molding).

[0004] In recent years, in the field of coating materials, many properties are required together with high heat resistance, such as mechanical properties, flame retardancy, abrasion resistance, chemical resistance, and excellent appearance properties in heat molding (extrusion molding).

[0005] Patent Document 1 describes that by adjusting the blending ratios of a water-crosslinkable polyolefin resin, a metal hydroxide, and a water-crosslinking catalyst to specific ratios, mechanical properties, heat resistance, and appearance properties can be improved.

[0006] Patent Document 2 describes an electrical wire coating material composition containing a silane-grafted polyolefin obtained by grafting a silane coupling agent onto a polyolefin, an unmodified polyolefin, a modified polyolefin modified with one or more functional groups selected from a carboxylic acid group, an acid anhydride group, an amino group, an acrylic group, a methacrylic group, and an epoxy group, magnesium hydroxide, a crosslinking catalyst, a silicone-modified polyurethane, an antioxidant, a metal deactivator, and a lubricant, which improves workability during wire handling by softening the coating film and provides an electrical wire coating material having high abrasion resistance and chemical resistance.

[0007] Patent Document 3 describes a flame-retardant resin composition excellent in extrusion appearance, hot set properties, oil resistance, etc., obtained by adding a polypropylene having a melting point of 135°C or higher and lower than 160°C, a propylene wax having a softening point of 140°C or higher and lower than 160°C, and a masterbatch of a silanol condensation catalyst to a flame-retardant compound obtained by silane-grafting a base polymer composed of an ethylene-α-olefin having a density of 0.880 g / cm 3 or higher and a polyethylene having a density of 0.950 g / cm 3 or higher.

[0008] Patent Document 4 describes a silane-crosslinked resin composition having excellent heat resistance while having an excellent appearance and a method for producing the same, by producing a flame-retardant compound obtained by silane-grafting an ethylene-vinyl acetate resin containing 0 to 45% by mass of an ethylene-vinyl acetate resin having a vinyl acetate content of 30% by mass or more and at least containing an ethylene-vinyl acetate resin having a vinyl acetate content of less than 30% by mass, with a total content of 5 to 100% by mass, using this as a base resin.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Patent Document 3

[0010] According to Patent Document 1 and Patent Document 4, although the appearance can be improved to some extent, further improvement is desired. In addition, in Patent Document 2, a lubricant is added to improve the extrusion appearance, but depending on the lubricant used, the improvement of the appearance may be insufficient. In Patent Document 3, the appearance can be improved to some extent by adding polypropylene wax to improve the extrusion appearance, but further improvement is desired.

[0011] The present invention has been made in view of the above circumstances, and an object thereof is to provide a resin composition, a crosslinked resin composition, a molded article, an electric wire coating material, and an electric wire having heat resistance, mechanical properties, flame retardancy, and excellent appearance. [Means for Solving the Problems]

[0012] As a result of intensive studies by the present inventor in view of the above problems, it has been found that among the compounds generally known as dehydrating agents, adding a specific compound to the resin composition exhibits a remarkable appearance improving effect.

[0013] That is, the present invention has the following gists [1] to [6]. [1] A resin composition containing the following (A), (B), (C), and (D). (A): A modified polyolefin graft-modified with an unsaturated silane compound (B): A metal hydroxide (C): A crosslinking catalyst (D): Zeolite and / or calcium oxide [2] A crosslinked resin composition obtained by subjecting the resin composition according to [1] to a crosslinking reaction. [3] A molded article using the crosslinked resin composition according to [2]. [4] An electric wire coating material made of the molded body described in [3]. [5] An electric wire coated with the electric wire coating material described in [4].

Advantages of the Invention

[0014] According to the present invention, there are provided a resin composition, a crosslinked resin composition, a molded body, an electric wire coating material, and an electric wire that have heat resistance, mechanical properties, and flame retardancy and are excellent in appearance.

Modes for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to the following description and can be arbitrarily modified and implemented without departing from the gist of the present invention. In this specification, when expressing with "~" sandwiching numerical values or physical property values before and after, it shall be used as including the values before and after.

[0016] [Resin Composition] The resin composition of the present invention is characterized by containing the following (A) to (D). (A): A modified polyolefin graft-modified with an unsaturated silane compound (B): A metal hydroxide (C): A crosslinking catalyst (D): Zeolite and / or calcium oxide

[0017] Hereinafter, each component used in the resin composition of the present invention will be described in detail.

[0018] (A): A modified polyolefin graft-modified with an unsaturated silane compound In the present invention, a modified polyolefin graft-modified with an unsaturated silane compound (hereinafter sometimes referred to as "silane-modified polyolefin (A)" or "component (A)") is a component mainly for imparting heat resistance to the resin composition, crosslinked resin composition, molded body, and electric wire coating material of the present invention.

[0019] The modified polyolefin (A) graft-modified with an unsaturated silane compound in the present invention means an uncrosslinked modified polyolefin resin. Usually, a modified polyolefin is preferably used so that it can be crosslinked with water.

[0020] The silane-modified polyolefin (A) is obtained by graft-modifying an unsaturated silane compound onto a polyolefin resin as a raw material listed below.

[0021] The polyolefin resin used as a raw material for the silane-modified polyolefin (A) (hereinafter sometimes referred to as the "raw material polyolefin resin") is not particularly limited. For example, homopolymers of α-olefins having about 2 to 8 carbon atoms such as ethylene, propylene, and 1-butene, and these α-olefins and other α-olefins having about 2 to 20 carbon atoms such as ethylene, propylene, 1-butene, 3-methyl-1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, and 1-decene, and copolymers with vinyl acetate, (meth)acrylic acid, (meth)acrylic acid esters, etc. are mentioned. Here, "(meth)acrylic acid" means one or both of "acrylic acid" and "methacrylic acid". The same applies to "(meth)acryloyl" described later.

[0022] Examples of the raw material polyolefin resin include ethylene homopolymers such as low-, medium-, and high-density polyethylene (branched or linear), ethylene-propylene copolymers, ethylene-1-butene copolymers, ethylene-4-methyl-1-pentene copolymers, ethylene-1-hexene copolymers, ethylene-1-octene copolymers, ethylene-vinyl acetate copolymers, ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylic acid ethyl copolymers, etc., propylene homopolymers, propylene-ethylene copolymers, propylene-1-butene copolymers, propylene-ethylene-1-butene copolymers, propylene-4-methyl-1-pentene copolymers, etc., and 1-butene homopolymers, 1-butene-ethylene copolymers, 1-butene-propylene copolymers, etc. These raw material polyolefin resins may be used alone or in combination of two or more.

[0023] Here, an ethylene-based resin, a propylene-based resin, and a 1-butene-based resin each refer to a resin containing ethylene units, propylene units, or 1-butene units at a ratio of 50% by mass or more in all monomer units constituting the resin.

[0024] Among these, as the polyolefin resin used as the raw material of the silane-modified polyolefin (A), an ethylene-based resin is preferable.

[0025] The silane-modified polyolefin (A) in the present invention is obtained by grafting an unsaturated silane compound onto a raw material polyolefin resin by a graft reaction using a free radical generator, as described later. If the raw material polyolefin resin is an ethylene-based resin, grafting can be preferably carried out, which is preferable. Further, if the raw material polyolefin resin is an ethylene-based resin, when the resin composition of the present invention is used for wire coating, the heat resistance is good, which is preferable. Among the above ethylene-based resins, an ethylene-1-butene copolymer, an ethylene-1-hexene copolymer, an ethylene-1-octene copolymer, an ethylene-vinyl acetate copolymer, and an ethylene-(meth)methyl acrylate copolymer are particularly preferable.

[0026] To obtain the silane-modified polyolefin (A) by graft-modifying the raw material polyolefin resin with an unsaturated silane compound, usually, the raw material polyolefin resin is subjected to a graft reaction step of an ethylenically unsaturated silane compound in the presence of a free radical generator such as an organic peroxide by a known method for graft modification. For example, a method of mixing a predetermined amount of an unsaturated silane compound and a free radical generator with the raw material polyolefin resin and melt-kneading at a temperature of 80 to 250°C can be used. At this time, if water is contained, the water cross-linking reaction proceeds, so it is preferable to melt-knead in a state without water.

[0027] Examples of the unsaturated silane compound used for graft modification include ethylenically unsaturated silane compounds represented by the following general formula (I). R 1 SiR 2 n Y 3-n …(I)

[0028] In the above formula (I), R 1 represents an ethylenically unsaturated hydrocarbon group or a hydrocarbon oxy group, R 2 represents a hydrocarbon group, Y represents a hydrolyzable organic group, and n is an integer of 0 to 2.

[0029] Here, examples of R 1 include a propenyl group, a butenyl group, a cyclohexenyl group, and a γ-(meth)acryloyloxypropyl group. Examples of R 2 include a methyl group, an ethyl group, a propyl group, a decyl group, and a phenyl group. Examples of Y include a methoxy group, an ethoxy group, a formyloxy group, an acetoxy group, a propionyloxy group, an alkylamino group, and an arylamino group.

[0030] Specific examples of such ethylenically unsaturated silane compounds include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, and γ-methacryloyloxypropyltrimethoxysilane. Among these, vinyltrimethoxysilane is preferably used from the viewpoint of odor and the like. One type or two or more types of unsaturated silane compounds may be used in combination.

[0031] The amount of the unsaturated silane compound used is not limited. From the viewpoint of obtaining a sufficient crosslinking effect and the heat resistance of the resin composition of the present invention, a larger amount is desirable, but from the viewpoint of processability, a smaller amount is desirable. Specifically, it is preferably 0.5 part by mass or more, more preferably 1.0 part by mass or more, based on 100 parts by mass of the raw material polyolefin resin. On the other hand, it is preferably 10 parts by mass or less, more preferably 5 parts by mass or less.

[0032] The free radical generator is not limited as long as it can graft an unsaturated silane compound onto the raw material polyolefin resin. However, organic peroxides such as dicumyl peroxide, 2,5-(tert-butylperoxy)hexine-3, and 1,3-bis(tert-butylperoxyisopropyl)benzene can be mainly used. These organic peroxides may be used alone or in combination of two or more.

[0033] The amount of the free radical generator used is not limited. It is desirable to use a larger amount in order for the unsaturated silane compound to be sufficiently graft copolymerized with the raw material polyolefin resin and obtain a sufficient crosslinking effect, but it is desirable to use a smaller amount from the viewpoint of processability. Specifically, it is preferably 0.01 part by mass or more, more preferably 0.02 part by mass or more, based on 100 parts by mass of the raw material polyolefin resin. On the other hand, it is preferably 0.2 part by mass or less, more preferably 0.1 part by mass or less.

[0034] The silane-modified polyolefin (A) used in the present invention preferably has a density of 0.850 to 0.960 g / cm 3 and more preferably 0.870 to 0.920 g / cm 3 As the density increases, the heat resistance, chemical resistance, abrasion resistance, flexure resistance, etc. of the obtained electric wire become better. On the other hand, as the density decreases, the flexibility becomes better.

[0035] The MFR of the silane-modified polyolefin (A) measured according to JIS K7210 at 190°C and a load of 2.16 kg is preferably larger from the viewpoint of moldability and preferably smaller from the viewpoint of mechanical properties. Specifically, the MFR of the silane-modified polyolefin (A) at 190°C and a load of 2.16 kg is preferably 0.1 g / 10 min or more, more preferably 1 g / 10 min or more. On the other hand, it is preferably 20 g / 10 min or less, more preferably 10 g / 10 min or less.

[0036] The silane-modified polyolefin (A) may be used alone, or two or more kinds having different monomer compositions, physical properties, etc. may be mixed and used.

[0037] As the silane-modified polyolefin (A), commercially available products can also be used. For example, the product named "Linkron" manufactured by Mitsubishi Chemical Corporation can be preferably used.

[0038] In the present invention, the blending ratio of the silane-modified polyolefin (A) is preferably 5% by mass or more, more preferably 8% by mass or more, in the whole composition. On the other hand, it is preferably 50% by mass or less, more preferably 40% by mass or less. If the blending ratio of the silane-modified polyolefin (A) is above the above lower limit, sufficient heat resistance can be obtained. On the other hand, if the blending ratio of the silane-modified polyolefin (A) is below the above upper limit, the deterioration of the molding appearance can be suppressed.

[0039] <(B): Metal hydroxide> In the present invention, the metal hydroxide (hereinafter, may be referred to as "metal hydroxide (B)" or "component (B)") is a component mainly for imparting flame retardancy to the resin composition, crosslinked resin composition, molded body, and wire coating material of the present invention.

[0040] The type of the metal hydroxide (B) is not limited, but specifically, magnesium hydroxide, aluminum hydroxide, calcium hydroxide, hydrotalcite can be mentioned. Among them, magnesium hydroxide and aluminum hydroxide are preferably used. These metal hydroxides (B) may be used alone or in combination of two or more.

[0041] As the metal hydroxide (B), those surface-treated with a surface treatment agent may be used. Examples of the surface treatment agent include silane-based coupling agents, titanate-based coupling agents, fatty acids or fatty acid metal salts. As a method for treating the metal hydroxide (B) with these surface treatment agents, known methods such as wet method, dry method, and direct kneading method can be used. By using the surface-treated metal hydroxide (B), the dispersibility in the obtained resin composition may be improved, and the mechanical properties may be improved.

[0042] The average particle diameter of the metal hydroxide (B) is preferably 2 μm or less, for example, 0.5 to 2 μm, from the viewpoints of mechanical properties, dispersibility, and flame retardancy. Here, the average particle diameter of the metal hydroxide (B) is the particle diameter at the time of 50% by volume cumulative distribution based on volume.

[0043] In the present invention, the blending ratio of the metal hydroxide (B) is preferably 45% by mass or more, more preferably 50% by mass or more, and on the other hand, preferably 65% by mass or less, more preferably 60% by mass or less, in the whole composition. If the blending ratio of the metal hydroxide (B) is at least the above lower limit, sufficient flame retardant performance can be obtained. On the other hand, if the blending ratio of the metal hydroxide (B) is at most the above upper limit, it is possible to prevent a decrease in productivity due to an increase in extrusion load and a decrease in mechanical properties.

[0044] <(C): Crosslinking catalyst> In the present invention, the crosslinking catalyst (hereinafter, may be referred to as "crosslinking catalyst (C)" or "component (C)") is a component for hydrolytically crosslinking the silane-modified polyolefin (A) contained in the resin composition of the present invention.

[0045] Since the silane-modified polyolefin (A) is a modified polyolefin graft-modified with an unsaturated silane compound, as the crosslinking catalyst (C), a compound capable of forming a crosslinked structure in the polyolefin resin by contacting with moisture in the presence of the crosslinking catalyst (C), so-called silanol condensation catalyst, is preferably used. Specific examples of the silanol condensation catalyst include metal fatty acid salts such as dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin diacetate, dibutyltin dioctoate, stannous acetate, stannous caprylate, zinc caprylate, lead naphthenate, and cobalt naphthenate.

[0046] As the crosslinking catalyst (C), only one kind may be used, or two or more kinds may be used in combination at an arbitrary combination and ratio.

[0047] In the present invention, the compounding ratio of the crosslinking catalyst (C) is preferably 0.0001% by mass or more, more preferably 0.0002% by mass or more, and on the other hand, preferably 0.02% by mass or less, more preferably 0.01% by mass or less, based on the whole composition. If the compounding ratio of the crosslinking catalyst (C) is at least the above lower limit, the crosslinking of the silane-modified polyolefin (A) proceeds sufficiently, and sufficient crosslinking characteristics can be obtained. On the other hand, if the compounding ratio of the crosslinking catalyst (C) is at most the above upper limit, it is possible to prevent a decrease in moldability due to excessive crosslinking.

[0048] <(D): Zeolite and / or calcium oxide> In the present invention, zeolite and / or calcium oxide (hereinafter sometimes referred to as "dehydrating agents (D)" or "component (D)") is a component mainly used to improve the molding appearance of the resin composition, crosslinked resin composition, molded article, and wire coating material of the present invention.

[0049] The effect of the dehydrating agents (D) in the present invention is presumed as follows. When the silane-modified polyolefin (A) is extrusion-molded, moisture is easily brought into the molding machine due to the moisture absorption of the metal hydroxide (B) or the like, and this causes an unintended crosslinking reaction during molding. The appearance deteriorates when the crosslinking reaction product appears as lumps (crosslinked lumps) on the surface of the molded article. The dehydrating agents (D) adsorb or remove moisture by reaction before an unintended crosslinking reaction occurs, so it is considered that crosslinked lumps are less likely to occur in the extruder and the molding appearance is improved.

[0050] The dehydrating agents (D) are preferably porous particles from the viewpoint of the dehydrating action of efficiently adsorbing moisture or efficiently removing moisture by reaction.

[0051] Among the dehydrating agents (D), zeolite preferably has a pore diameter of 3 Å or more, more preferably 9 Å or more. If the pore diameter is 3 Å or more, particularly 9 Å or more, it is likely to adsorb moisture and tends to sufficiently exhibit the effect of improving the appearance. Although the detailed reason for the large effect of improving the appearance by zeolite with a large pore diameter has not been clearly clarified, it is conceivable that zeolite with a large pore diameter adsorbs not only moisture but also light volatile components other than moisture, which may have a favorable effect on the appearance of the molded body. There is no particular limitation on the crystal form, but those of A type and X type are preferred.

[0052] As the dehydrating agents (D), those surface-treated with a surface treatment agent may be used. Examples of the surface treatment agent include silane-based coupling agents, titanate-based coupling agents, fatty acids, or fatty acid metal salts. By using those surface-treated as the dehydrating agents (D), the dispersibility in the resulting resin composition may be improved, and the mechanical properties may be improved in some cases.

[0053] Only one type of the dehydrating agents (D) may be used, or two or more types may be used in combination. For example, two or more types of dehydrating agents (D) having different pore diameters and crystal forms may be mixed and used.

[0054] In the case of zeolite, the blending ratio of the dehydrating agents (D) is preferably 0.01% by mass or more, more preferably 0.015% by mass or more, and on the other hand, preferably 5.0% by mass or less, more preferably 3.0% by mass or less, based on the whole composition. In the case of calcium oxide, the blending ratio is preferably 0.001% by mass or more, more preferably 0.05% by mass or more, and on the other hand, preferably 5.0% by mass or less, more preferably 3.0% by mass or less, based on the whole composition. When zeolite and calcium oxide are used in combination as the dehydrating agents (D), the blending ratio of each is within the above range, and the total blending ratio of these is preferably 0.01% by mass or more, particularly 0.05% by mass or more, and 5.0% by mass or less, particularly 3.0% by mass or less, based on the whole composition. If the blending ratio of the dehydrating agents (D) is at least the above lower limit, a sufficient dehydrating effect can be obtained and a good molding appearance can be obtained. On the other hand, if the blending ratio of the dehydrating agents (D) is at most the above upper limit, a decrease in physical properties due to the addition of the dehydrating agent can be suppressed.

[0055] <Other components> In the resin composition of the present invention, additives, resins, etc. other than the above-described components (A) to (D) may be included as "other components" as necessary within a range that does not significantly impede the effects of the present invention. As the other components, only one type may be used, or two or more types may be used in combination at an arbitrary combination and ratio. Further, in the case of producing the resin composition using a flame retardant masterbatch, a catalyst masterbatch, and a dehydration masterbatch as described later, the other components may be contained in any of the masterbatches.

[0056] There are no particular restrictions on the resin components other than the above-described silane-modified polyolefin (A) blended as the other components, but unmodified polyethylene and / or acid-modified polyethylene (hereinafter sometimes referred to as "unmodified / acid-modified polyethylene (E)" or "component (E)") can be mentioned. The unmodified / acid-modified polyethylene (E) mainly functions as a component for improving the mechanical properties and moldability in the resin composition, crosslinked resin composition, molded article, and wire coating material of the present invention.

[0057] Unmodified polyethylene is polyethylene that has not been modified with a silane coupling agent, a functional group, or the like. The polyethylene referred to here is polyethylene (ethylene homopolymer or ethylene-based copolymer) containing ethylene units at a ratio of 50% by mass or more in all constituent monomer units.

[0058] Here, polyethylene may be a copolymer of ethylene and other α-olefins having about 3 to 20 carbon atoms such as propylene, 1-butene, 3-methyl-1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, etc., or may be a copolymer of ethylene with vinyl acetate, (meth)acrylic acid, (meth)acrylate, etc.

[0059] Regarding acid-modified polyethylene, as the polyethylene used, those exemplified as the above-mentioned unmodified polyethylene are preferably used in terms of compatibility. The type of acid used for acid-modifying polyethylene is not particularly limited, but maleic anhydride is particularly preferred. The acid modification of polyethylene can be carried out according to a conventional method.

[0060] The unmodified / acid-modified polyethylene (E) preferably has a density of 0.850 to 0.970 g / cm 3 Those with a density of 0.850 g / cm 3 or more will result in good heat resistance, chemical resistance, abrasion resistance, flexural resistance, etc. of the obtained electric wire, and those with a density of 0.970 g / cm 3 or less will have good flexibility.

[0061] The unmodified / acid-modified polyethylene (E) preferably has an MFR of 1 to 10 g / 10 min at 190 °C and a load of 2.16 kg measured according to JIS K7210. Similar to the regulation of the MFR of the silane-modified polyolefin (A), in terms of moldability, a larger MFR is preferred as it can improve the production amount per unit time, and in terms of mechanical properties and heat resistance, a smaller MFR is preferred.

[0062] The unmodified / acid-modified polyethylene (E) may be used alone, or two or more kinds with different monomer compositions and physical properties may be mixed and used.

[0063] When the resin composition of the present invention contains unmodified / acid-modified polyethylene (E), the blending ratio of the unmodified / acid-modified polyethylene (E) is preferably 1% by mass or more, more preferably 2% by mass or more, in the whole composition. On the other hand, it is preferably 30% by mass or less, more preferably 25% by mass or less. If the blending ratio of the unmodified / acid-modified polyethylene (E) is at least the above lower limit, sufficient mechanical properties and moldability can be obtained. On the other hand, if the blending ratio of the unmodified / acid-modified polyethylene (E) is at most the above upper limit, a decrease in heat resistance can be prevented.

[0064] As resins other than the silane-modified polyolefin (A) and the unmodified / acid-modified polyethylene (E), in addition to the aforementioned raw material polyolefin resins, for example, polyphenylene ether-based resins; polycarbonate resins; polyamide-based resins such as nylon 66 and nylon 11; polyester-based resins such as polyethylene terephthalate and polybutylene terephthalate, styrene-based resins such as polystyrene, and acrylic / methacrylic-based resins such as polymethyl methacrylate-based resins and various thermoplastic elastomers can be mentioned.

[0065] Specific examples of the additives include process oil, processing aids, plasticizers, crystal nucleating agents, impact modifiers, flame retardants other than metal hydroxides (B), flame retardant aids, crosslinking aids, antistatic agents, antioxidants, lubricants, fillers, compatibilizers, heat stabilizers, light stabilizers, ultraviolet absorbers, carbon black, and colorants.

[0066] Flame retardants other than metal hydroxides (B) are roughly classified into halogen-based flame retardants and non-halogen-based flame retardants, and non-halogen-based flame retardants are preferred. Examples of non-halogen-based flame retardants other than metal hydroxides (B) include phosphorus-based flame retardants, nitrogen-containing compound (melamine-based, guanidine-based) flame retardants, and inorganic compound (borate, molybdenum compound) flame retardants.

[0067] Examples of heat stabilizers and antioxidants include hindered phenols, phosphorus compounds, hindered amines, sulfur compounds, copper compounds, and alkali metal halides.

[0068] The filler is roughly classified into an organic filler and an inorganic filler. Examples of the organic filler include natural polymers such as starch, cellulose fine particles, wood powder, okara, rice husk, bran, and modified products thereof. Examples of the inorganic filler include talc, calcium carbonate, zinc carbonate, wollastonite, silica, alumina, magnesium oxide, calcium silicate, sodium aluminate, calcium aluminate, sodium aluminosilicate, magnesium silicate, glass balloon, carbon black, zinc oxide, antimony trioxide, zeolite, hydrotalcite, metal fiber, metal whisker, ceramic whisker, potassium titanate, boron nitride, graphite, carbon fiber, and the like.

[0069] Further, the resin composition of the present invention may contain a softening agent for hydrocarbon rubber. As the softening agent for hydrocarbon rubber, a mineral oil-based or synthetic resin-based softening agent is preferable, and a mineral oil-based softening agent is more preferable. The mineral oil-based softening agent is generally a mixture of aromatic hydrocarbons, naphthenic hydrocarbons, and paraffinic hydrocarbons. Those in which 50% or more of all carbon atoms are paraffinic hydrocarbons are called paraffin oils, those in which about 30 to 45% or more of all carbon atoms are naphthenic hydrocarbons are called naphthenic oils, and those in which 35% or more of all carbon atoms are aromatic hydrocarbons are called aromatic oils of carbon atoms, respectively. As the softening agent for hydrocarbon rubber, it is preferable to use any one selected from paraffin oil, naphthenic oil, and aromatic oil of carbon atoms. Among these, paraffin oil is more preferably used because of its good hue. Examples of the synthetic resin-based softening agent include polybutene and low molecular weight polybutadiene.

[0070] When the resin composition of the present invention contains these additives, resins, and other components, the content ratio thereof is not limited, but it is preferable that the total ratio of components (A) to (D) occupies 50% by mass or more of the resin composition of the present invention.

[0071] <Method for Producing Resin Composition> The method for producing the resin composition of the present invention is not particularly limited, as long as it can be produced to contain a silane-modified polyolefin (A), a metal hydroxide (B), a crosslinking catalyst (C), and dehydrating agents (D). The resin composition of the present invention can be produced, for example, by mixing each component simultaneously or in any order. Specifically, (1) A method of first kneading the silane-modified polyolefin (A) and the metal hydroxide (B), and then adding the crosslinking catalyst (C) and the dehydrating agents (D) (2) A method of first kneading the silane-modified polyolefin (A), the metal hydroxide (B), and the dehydrating agents (D), and then adding the crosslinking catalyst (C) (3) A method of kneading all of them together and so on. Other components such as antioxidants and colorants may be added at any timing as long as they can be uniformly dispersed.

[0072] There is no limitation on the apparatus for mixing the above raw material components, but general-purpose ones such as a kneader, a Banbury mixer, rolls, a single-screw extruder, and a twin-screw extruder can be used. The temperature during melt mixing may be a temperature at which at least one of the raw material components is in a molten state, but usually, a temperature at which all the components used are melted is selected, and generally, it is carried out at 150 to 250°C.

[0073] As a preferable method for producing the resin composition of the present invention, a masterbatch in which a metal hydroxide (B) is contained in a silane-modified polyolefin (A) or the like (hereinafter referred to as "flame retardant masterbatch"), and a crosslinking catalyst (C) is contained in a resin other than the silane-modified polyolefin (A) (for example, the aforementioned unmodified / acid-modified polyethylene (E)) The masterbatch (hereinafter referred to as "catalyst masterbatch") and the dehydrating agents (D) are contained in a resin other than the silane-modified polyolefin (A) (for example, the aforementioned unmodified / acid-modified polyethylene (E)) The masterbatch (hereinafter referred to as "dehydration masterbatch") is separately manufactured and mixed to produce, or the flame retardant masterbatch, the crosslinking catalyst (C) and the dehydrating agents (D) are contained in a resin other than the silane-modified polyolefin (A) (for example, the aforementioned unmodified / acid-modified polyethylene (E)) The masterbatch (hereinafter referred to as "dehydration / catalyst masterbatch") is separately manufactured and mixed to produce, which is preferable.

[0074] Thus, by using the flame retardant masterbatch, the catalyst masterbatch, and the dehydration masterbatch, or the flame retardant masterbatch and the dehydration / catalyst masterbatch, it is possible to suppress the progress of the crosslinking reaction before obtaining the molded body.

[0075] There is no limitation on the method for producing the flame retardant masterbatch, and the above-described apparatus can be used in the same manner. As the manufacturing process, (1) A step of producing the silane-modified polyolefin (A), that is, a step of grafting a silane compound (2) A step of mixing the silane-modified polyolefin (A) and the metal hydroxide (B) and other components There are two of these, and these may be carried out separately, or both steps may be carried out at once using, for example, a twin-screw extruder or the like, but the former is preferable.

[0076] There is no limitation on the method for producing the catalyst masterbatch, the dehydration masterbatch, and the dehydration / catalyst masterbatch, and the above-described apparatus can be used in the same manner.

[0077] When mixing the flame retardant masterbatch, the catalyst masterbatch, and the dehydrating masterbatch, or the flame retardant masterbatch and the dehydrating-catalyst masterbatch, the above-described apparatus can be used in the same manner.

[0078] <Water crosslinking treatment> Since the resin composition of the present invention is water crosslinkable, a crosslinked structure can be formed in the resin composition by contacting it with moisture. The water crosslinking treatment is carried out by contacting with liquid or vaporous water at normal temperature to about 200°C, usually normal temperature to about 100°C, for about 10 seconds to 1 week, usually about 1 minute to 1 day. However, even without such treatment, it is possible to crosslink by moisture in the air.

[0079] By subjecting the resin composition of the present invention to water crosslinking treatment, a crosslinked resin composition excellent in heat resistance, mechanical properties, flame retardancy, and appearance can be obtained.

[0080] <Molded articles and uses> The method for molding the resin composition of the present invention is not particularly limited, such as extrusion molding, compression molding, injection molding, etc. However, from the viewpoint of the fluidity of the resin composition in the molten state, extrusion molding is desirable. Also, the molding temperature is not limited as long as it is higher than the melting temperature of the resin composition, but 150°C to 200°C is desirable. If the molding temperature is above the above lower limit, the fluidity of the molten resin composition is high, and it is easy to obtain a molded body of the desired shape. On the other hand, if the molding temperature is below the above upper limit, foaming due to the decomposition of the metal hydroxide (B) and deterioration of the appearance due to crosslinked lumps are less likely to occur.

[0081] Incidentally, it is preferable that the resin composition of the present invention is molded into a desired shape in advance before performing the water crosslinking treatment, and then the water crosslinking treatment is carried out. Since the resin composition of the present invention has good moldability, for example, when extrusion molding is performed, a molded body with a smooth surface and no scorch (burn marks) and other good appearance can be obtained. Further, by subjecting this molded body to water crosslinking treatment, a molded body of a water crosslinked resin composition with a good appearance similar to that before water crosslinking can be obtained.

[0082] The use of the molded article obtained by using the resin composition of the present invention is not particularly limited. However, since it has excellent heat resistance, mechanical properties, and flame retardancy and has an excellent appearance, it can be suitably used for insulators and sheaths for electric wires and cables. Furthermore, in addition to tubes for bundling a plurality of resin-coated electric wires, it can be suitably used for various insulating films, insulating pipes, power boxes, and the like. Among those listed above, the resin composition of the present invention is particularly preferably used for electric wires as an electric wire coating material.

Examples

[0083] Hereinafter, specific embodiments of the present invention will be described in more detail using examples. However, the present invention is not limited by the following examples as long as the gist thereof is not exceeded. In addition, the values of various manufacturing conditions and evaluation results in the following examples have the meaning as preferable values of the upper limit or the lower limit in the embodiments of the present invention, and the preferable range may be a range defined by a combination of the above-mentioned upper limit or lower limit values and the values of the following examples or the values between the examples.

[0084] [Raw materials] In the following examples and comparative examples, the following raw materials were used.

[0085] <Component (A): Silane-modified polyolefin> · Silane graft polyolefin - 1: Trade name Linkron SH710N (manufactured by Mitsubishi Chemical Corporation, MFR: 2 g / 10 min, density: 0.892 g / cm 3 , content ratio of ethylene units in all monomer units constituting: 50 mass% or more) · Silane graft polyolefin - 2: Trade name Linkron HF800N (manufactured by Mitsubishi Chemical Corporation, MFR: 1.5 g / 10 min, density: 0.943 g / cm 3 , content ratio of ethylene units in all monomer units constituting: 50 mass% or more)

[0086] <Component (B): Metal hydroxide> · Metal hydroxide - 1: Magnesium hydroxide Trade name Magsees S - 6 (manufactured by Kojima Chemical Industry Co., Ltd., average particle diameter: 1.0 μm) · Metal hydroxide - 2: Magnesium hydroxide, trade name KISUMA5P (manufactured by Kyowa Chemical Industry Co., Ltd., average particle diameter: 0.8 μm)

[0087] <Component (C): Crosslinking catalyst> · Dioctyltin dilaurate (manufactured by Nitto Kasei Co., Ltd.)

[0088] <Component (D): Dehydrating agents> · Dehydrating agent - 1: Zeolite, trade name Zeolam A - 5 (manufactured by Tosoh Corporation, type A zeolite, pore diameter: 5 Å) · Dehydrating agent - 2: Zeolite, trade name Zeolam F - 9 (manufactured by Tosoh Corporation, type X zeolite, pore diameter: 9 Å) · Dehydrating agent - 3: Zeolite, trade name Molecular sieve 5A (manufactured by Union Showa Co., Ltd., type A zeolite, pore diameter: 5 Å) · Dehydrating agent - 4: Zeolite, trade name Molecular sieve 13X (manufactured by Tosoh Corporation, type X zeolite, pore diameter: 9 Å) · Dehydrating agent - 5: Zeolite, trade name Mizukasebs 5AP (manufactured by Mizusawa Chemical Industry Co., Ltd., type A zeolite, pore diameter: 5 Å) · Dehydrating agent - 6: Calcium oxide, trade name F lime 1300K (manufactured by Calfine Co., Ltd.)

[0089] <Component (E): Unmodified / acrylic - modified polyethylene> · Polyethylene - 1: Ethylene - vinyl acetate copolymer, trade name Evaflex EV40LX (manufactured by Mitsui - DuPont Polychemical Co., Ltd., MFR: 2 g / 10 min, density: 0.970 g / cm 3 , vinyl acetate unit content ratio: 41 mass%) · Polyethylene - 2: Maleic anhydride - modified polyethylene, trade name Modic MMHDH1 (manufactured by Mitsubishi Chemical Corporation, MFR: 1 g / 10 min, density: 0.955 g / cm 3 ) · Polyethylene - 3: Ethylene - 1 - butene copolymer, trade name Engage7256 (manufactured by Dow Chemical Japan Co., Ltd., MFR: 2.5 g / 10 min, density: 0.885 g / cm 3 ) · Polyethylene - 4: High - density polyethylene, trade name Novatech HJ362 (manufactured by Japan Polyethylene Corporation, MFR: 5 g / 10 min, density: 0.953 g / cm 3 )

[0090] <Other resins> · SEBS: Styrene - ethylene - butylene - styrene block copolymer, trade name TAIPOL SEBS - 6151A (manufactured by Japan Chemtech Co., Ltd., density: 0.91 g / cm 3 )

[0091] <Other dehydrating agents> · Dehydrating agent - 7: Aluminum oxide - magnesium oxide solid solution, trade name Kyoward 2200 (manufactured by Kyowa Chemical Industry Co., Ltd.) · Dehydrating agent - 8: Activated alumina, trade name KC - 501 (manufactured by Sumitomo Metal Industries, Ltd.) · Dehydrating agent - 9: Magnesium oxide, trade name Kyowamag 30 (manufactured by Kyowa Chemical Industry Co., Ltd.)

[0092] <Other additives> · Mineral oil: Process oil, trade name Diana Process Oil PW - 90 (manufactured by Idemitsu Kosan Co., Ltd., density: 0.87 g / cm 3 ) · Antioxidant: Pentaerythritol tetrakis[3 - (3,5 - di - t - butyl - 4 - hydroxyphenyl)propionate], trade name Irganox 1010 (manufactured by BASF Japan Ltd.)

[0093] [Production Example 1: Production of Flame - Retardant Masterbatch - 1 and 2] The raw materials shown in Table - 1 were charged into a pressure kneader with an internal volume of 1.0 L at the compounding amounts shown in Table - 1 and kneaded at a set temperature of 170°C for 15 minutes. The obtained kneaded product was further sheeted by a roll and then pelletized by a pelletizer to produce flame - retardant masterbatch - 1 and 2.

[0094] [Production Example 2: Production of Catalyst Masterbatch] A mixture of polyethylene-3, a crosslinking catalyst (C), and an antioxidant in a ratio of 100 / 0.1 / 1 parts by mass was prepared, and this was extruded at a resin temperature of 200 °C using a 40 mmφ single-screw extruder (L / D = 24, full-flight screw: compression ratio 2.7). The extruded strands were pelletized with a pelletizer to produce a catalyst masterbatch.

[0095] [Production Example 3: Production of Dehydration Masterbatches - 1 to 8] The raw materials shown in Table-2 were charged into a pressure kneader with an internal volume of 1.0 L at the compounding amounts shown in Table-2 and kneaded at a set temperature of 90 °C for 10 minutes. The obtained kneaded product was further sheeted by a roll and then pelletized with a pelletizer to produce dehydration masterbatches - 1 to 8.

[0096]

Table 1

[0097]

Table 2

[0098] [Appearance Evaluation of Extruded Sheet] A flame retardant masterbatch, a catalyst masterbatch, and a dehydration masterbatch were mixed at the ratios shown in Table-3, and this was supplied to a 20 mmφ single-screw extruder (L / D = 22, full-flight screw: compression ratio 2.5) equipped with a die having a thickness of 0.5 mm × width of 45 mm and continuously extruded for 60 minutes. The appearance of the sheet was observed every 3 m over time, and those with 0 to 9 surface bumps (tubular substances on the surface of the molded body) per 1 m of the sheet were rated as "◎", those with 10 to 19 as "○", those with 20 to 59 as "△", those with 60 to 99 as "×", and those with 100 or more as "××".

[0099] [Examples 1 to 7, Comparative Examples 1 to 5] The appearance of the sheet was observed at 10 minutes, 30 minutes, and 60 minutes respectively when continuously extruded at an extrusion resin temperature of 200 °C for 60 minutes, and the appearance was judged. The judged results are shown in Table-3.

[0100] In Comparative Examples 1 and 2 without adding the dehydration masterbatch, a large amount of lumps occurred at the 10-minute mark, and an even larger amount of lumps occurred at 30 minutes, resulting in a poor appearance. This is presumably because unintended crosslinking occurred relatively early inside the extruder, and the crosslinking reaction product appeared as lumps on the sheet.

[0101] Examples 1 to 7 with the addition of dehydration masterbatches -1 to 5 maintained a good appearance. Among these, in particular, Examples 1 and 3 containing X-type zeolite (dehydrating agent) with a pore diameter of 9 Å, and Examples 4 and 5 with a certain amount or more of calcium oxide added showed good results. This is presumably because, even in the environment inside the extruder reaching nearly 200 °C, a high water absorption capacity was exhibited, resulting in the suppression of the occurrence of unintended water crosslinking reactions.

[0102] On the other hand, in Comparative Examples 3 to 5 using dehydration masterbatches -6 to 8 containing dehydrating agents -7 to 9, which are generally known to have a dehydrating effect but are not component (D), a large amount of lumps occurred at the 10-minute mark and the appearance was poor. This is presumably because water removal inside the extruder was not sufficient, and an unintended crosslinking reaction occurred relatively early, causing the crosslinking reaction product to appear as lumps on the sheet.

[0103]

Table 3

[0104] From the above results, it can be seen that according to the present invention, a resin composition containing a flame retardant component and a heat-resistant component, thus having heat resistance, mechanical properties, and flame retardancy, and excellent in molding appearance, is provided.

Claims

Claim 1 A resin composition comprising the following (A), (B), (C), and (D). (A): A modified polyolefin graft-modified with an unsaturated silane compound (B): A metal hydroxide (C): A crosslinking catalyst (D): Zeolite having a pore diameter of 3 Å or more and / or calcium oxide Claim 2 The resin composition according to claim 1, wherein (D) is zeolite having a pore diameter of 5 Å or more and / or calcium oxide. Claim 3 A crosslinked resin composition obtained by subjecting the resin composition according to claim 1 or 2 to a crosslinking reaction. Claim 4 A molded article using the crosslinked resin composition according to claim 3. Claim 5 An electric wire coating material comprising the molded article according to claim 4. Claim 6 An electric wire coated with the electric wire coating material according to claim 5.

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