JP2010257950A - Radiation curing resin composition for coating wire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation curing resin composition for coating wires, producing satisfactory efficiency for manufacturing a coating layer, having sufficient strength and satisfactory adhesion to a center conductor. <P>SOLUTION: This radiation curing resin composition for coating wires contains the following components (A), (B), and (D); (A) a mixture of urethane (meta) acrylate having a structure derived from aliphatic polyol, urethane (metha) acrylate having a structure derived from cyclic polyol, and urethane (metha) acrylate not having a structure derived from polyol, (B) a compound having a cyclic structure and one ethylenic unsaturated group, (D) a compound expressed by the formula (4a). (In the formula (4a), R<SP>8</SP>is a univalent organic group which has an ethylenic unsaturated group, and R<SP>9</SP>is a univalent organic group which may have a hydrogen atom or an ethylenic unsaturated group). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a resin composition for coating such as electric wires, particularly power wires, telephone wires, connecting wires between electronic devices or in electronic devices.

  Power cables, cables, telephone cables, connecting cables between or within electronic devices, automotive cables, etc., are made of polyethylene (PE) with excellent electrical and transmission characteristics as insulators, and PE is used as the outer sheath. Many of them use polyvinyl chloride (PVC). In television lead wires, PE coating or rubber using outer sheath is used. Also, PVC, PET, cross-linked PE and the like are widely used for covering automobile wires (Patent Documents 1 to 4). Moreover, the example which used the radiation curable resin for the electric wire coating layer is also disclosed (patent document 5).

JP 2001-312925 A JP 2005-187595 A JP 2006-348137 A JP 2007-45952 A JP 2008-251435 A

However, although the conventional wire coating material is strongly required to have a strong strength as a protective material, the production efficiency of the coating layer and the adhesion to the central conductor may be insufficient.
Accordingly, an object of the present invention is to provide a resin composition for coating an electric wire that has good production efficiency of a coating layer, has sufficient strength, and has good adhesion to a central conductor.

  Accordingly, the present inventors have focused on urethane (meth) acrylate radiation curable resin compositions to develop a wire covering material that can replace conventional PVC and PE, and as a result of various studies, have found that urethane (meta) having a specific structure. ) Use of a combination of an acrylate, a compound having a cyclic structure and one ethylenically unsaturated group, and a specific compound having a phosphate ester structure provides good coating layer production efficiency and sufficient strength. Nevertheless, the present inventors have found that an electric wire covering material having good adhesion to the central conductor can be obtained, and the present invention has been completed.

That is, the present invention includes the following components (A), (B) and (D);
(A) a mixture of urethane (meth) acrylate having a structure derived from an aliphatic polyol, urethane (meth) acrylate having a structure derived from a cyclic polyol, and urethane (meth) acrylate having no structure derived from a polyol,
(B) a compound having a cyclic structure and one ethylenically unsaturated group,
(D) Compound represented by the following formula (4a)

(In formula (4a), R ⁸ is a monovalent organic group having an ethylenically unsaturated group, and R ⁹ is a monovalent organic group optionally having a hydrogen atom or an ethylenically unsaturated group. )
The radiation curable resin composition for electric wire coating | cover containing is provided.

  In the present invention, the electric wire coating layer (sometimes simply referred to as a coating layer) is a resin coating layer used for electric wires, and is a resin coating provided outside a central conductor made of a metal wire such as copper or aluminum. There is no particular limitation as long as it is a layer, and typically, an insulation layer of an insulated wire having an insulation layer covering the central conductor, a sheath layer of a cable in which one or more insulated wires are covered with a sheath layer, and a shield The sheath layer provided in contact with the outer side of the shield layer of the cable having a layer is included. Moreover, an electric wire coating material means the resin composition used for manufacture of an electric wire coating layer.

By using the composition of the present invention, an electric wire coating layer having excellent strength (particularly strength represented by Young's modulus and elongation at break) and heat resistance can be easily and uniformly formed by irradiation with ultraviolet rays or the like, and the protection. The layer has good adhesion to the central conductor, and the wire coating layer can be produced efficiently.
By using the radiation-curing wire coating material of the present invention, it is possible to obtain a wire having sufficient strength even with a thin coating layer, so that a power wire, for example, a power wire such as a motor coil, It can be particularly preferably used.

Hereafter, each component which comprises the composition of this invention is demonstrated.
The urethane (meth) acrylate which is the component (A) of the present invention includes (A1) urethane (meth) acrylate having a structure derived from an aliphatic polyol, and (A2) urethane (meth) acrylate having a structure derived from a cyclic polyol. And (A3) a mixture of urethane (meth) acrylates having no polyol-derived structure.

(A1) Urethane (meth) acrylate having a structure derived from an aliphatic polyol has a relatively flexible structure derived from an aliphatic polyol, so the Young's modulus of the cured product is decreased and the elongation at break is increased. Thus, for example, resistance to bending stress applied when winding a covered electric wire or the like around a bobbin can be improved. The component (A1) preferably has a structure represented by the following formula.
HA- (DI-aPOL-) _m -DI-HA
[In the above formula, aPOL is a structure derived from an aliphatic polyol, DI is a structure derived from diisocyanate, and HA is a structure derived from a hydroxyl group-containing (meth) acrylate. m is 1-4 and 1 is preferable. ]

(A2) The urethane (meth) acrylate having a structure derived from a cyclic polyol has a relatively rigid structure derived from a polyol having a cyclic structure, so that the Young's modulus of the cured product is increased and the elongation at break is increased. The central conductor can be effectively protected when the external stress is applied. The component (A2) preferably has a structure represented by the following formula.
HA- (DI-cPOL-) _n -DI-HA
[In the above formula, cPOL is a structure derived from a cyclic polyol, DI is a structure derived from a diisocyanate, and HA is a structure derived from a hydroxyl group-containing (meth) acrylate. n is 1-4 and 1 is preferable. ]

(A3) A urethane (meth) acrylate having no polyol-derived structure does not have a polyol-derived structure, and has a relatively small molecular weight and a rigid structure. In addition, since the component (A3) has a low molecular weight, the density of urethane bonds can be increased, and the density of hydrogen bonds formed in the cured product is increased to form a wire coating layer with excellent resistance to external stress. can do. The component (A3) preferably has a structure represented by the following formula.
HA-DI-HA
[In the above formula, DI is a structure derived from diisocyanate, and HA is a structure derived from a hydroxyl group-containing (meth) acrylate. ]

  By using urethane (meth) acrylate having a specific structure represented by (A), it is possible to form an electric wire coating layer having excellent heat resistance and good adhesion to the central conductor.

The urethane (meth) acrylate as the component (A) has a structure derived from an aliphatic polyol obtained by reacting (a1) an aliphatic polyol, (b) a polyisocyanate, and (c) a hydroxyl group-containing (meth) acrylate. Urethane (meth) having a structure derived from cyclic polyol obtained by reacting urethane (meth) acrylate (A1), (a2) cyclic polyol, (b) polyisocyanate and (c) hydroxyl group-containing (meth) acrylate Mixing urethane (meth) acrylate (A3) having no polyol-derived structure obtained by reacting (b) polyisocyanate and (c) hydroxyl group-containing (meth) acrylate without using acrylate (A2) and polyol Obtainable.
(A) Urethane (meth) acrylate can also be obtained by reacting (a1) aliphatic polyol, (a2) cyclic polyol, (b) polyisocyanate and (c) hydroxyl group-containing (meth) acrylate. . In this case, the amount of the synthetic raw materials (a1), (a2), (b) and (c) used is the desired mass ratio of (A1), (A2) and (A3) and each urethane (meth) acrylate. It is preferable to calculate and determine the molar ratio of each raw material that is theoretically required from the structure.

  (A1) The aliphatic polyol is not particularly limited as long as it has an aliphatic structure and does not have a cyclic structure such as an aromatic ring structure or an alicyclic structure. For example, polyethylene glycol, polypropylene glycol, Examples thereof include polytetramethylene glycol, polyhexamethylene glycol, polyheptamethylene glycol, polydecamethylene glycol, and aliphatic polyether polyols obtained by ring-opening copolymerization of two or more ion-polymerizable cyclic compounds. Examples of the ion polymerizable cyclic compound include ethylene oxide, propylene oxide, butene-1-oxide, isobutene oxide, tetrahydrofuran, 2-methyltetrahydrofuran, and 3-methyltetrahydrofuran. Specific combinations of the two or more ion-polymerizable cyclic compounds include, for example, tetrahydrofuran and propylene oxide, tetrahydrofuran and 2-methyltetrahydrofuran, tetrahydrofuran and 3-methyltetrahydrofuran, tetrahydrofuran and ethylene oxide, propylene oxide and ethylene oxide, butene-1 And terpolymers of -oxide and ethylene oxide, tetrahydrofuran, butene-1-oxide, ethylene oxide, and the like. Among these, polypropylene glycol and polytetramethylene glycol are preferable.

  (A) The molecular weight of the (a1) aliphatic polyol used for the synthesis of urethane (meth) acrylate is preferably 1,000 to 4,000 as a polystyrene-equivalent number average molecular weight determined by gel permeation chromatography. , 500 to 2,500 are more preferable. (A1) When the molecular weight of the polyol is in the above range, the mechanical properties of the electric wire coating layer, particularly the elongation at break can be made a preferable range.

  (A1) Examples of commercially available aliphatic polyols include PTMG650, PTMG1000, PTMG2000 (manufactured by Mitsubishi Chemical), PPG-400, PPG1000, PPG2000, PPG3000, PPG4000, EXCENOL720, 1020, 2020 (and above, manufactured by Asahi Glass Urethane). ), PEG1000, Unisafe DC1100, DC1800 (above, manufactured by NOF Corporation), PPTG2000, PPTG1000, PTG400, PTGL2000 (above, manufactured by Hodogaya Chemical), Z-3001-4, Z-3001-5, PBG2000A, PBG2000B (above, Daiichi Kogyo Seiyaku Co., Ltd.) can be used, and products having a suitable molecular weight can be selected from these commercially available products according to the type of urethane (meth) acrylate to be synthesized.

  (A2) The cyclic polyol is not particularly limited as long as it is a polyol having a cyclic structure such as an aromatic ring structure or an alicyclic structure. For example, an alkylene oxide addition polyol of bisphenol A, an alkylene oxide addition polyol of bisphenol F , Hydrogenated bisphenol A, hydrogenated bisphenol F, alkylene oxide addition polyol of hydrogenated bisphenol A, alkylene oxide addition polyol of hydrogenated bisphenol F, alkylene oxide addition polyol of hydroquinone, alkylene oxide addition polyol of naphthohydroquinone, alkylene of anthrahydroquinone Oxide addition polyol, 1,4-cyclohexane polyol and its alkylene oxide addition polyol, tricyclodecane polyol, tri Black decanedimethanol, penta cyclopentadecane polyols, pentacyclopentadecanedimethanol, alkylene oxide addition polyol, alkylene oxide addition polyol of bisphenol F, alkylene oxide addition polyol of 1,4-cyclohexane polyol. Among these, an alkylene oxide addition polyol of bisphenol A is preferable.

  (A2) The preferable molecular weight of the cyclic polyol is preferably from 300 to 1,000, more preferably from 300 to 800, as a polystyrene-equivalent number average molecular weight determined by gel permeation chromatography. (A2) When the molecular weight of the polyol is in the above range, the mechanical properties of the electric wire coating layer, particularly the elongation at break can be made a preferable range.

  As the (a2) cyclic polyol, for example, UNIOL DA400, DA700, DA1000, DB400 (manufactured by NOF Corporation), tricyclodecane dimethanol (manufactured by Mitsubishi Chemical Corporation) and the like can be obtained as commercial products.

  In addition, as the (a1) aliphatic polyol and (a2) cyclic polyol, polyester polyol, polycarbonate polyol, polycaprolactone polyol, and the like can be used in addition to the polyether polyol.

  (B) Polyisocyanate, particularly diisocyanate, for example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, 1,5-naphthalene Diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 3,3′-dimethyl-4,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate, 3,3′-dimethylphenylene diisocyanate, 4,4′-biphenylene Diisocyanate, 1,6-hexane diisocyanate, isophorone diisocyanate, methylenebis (4-cyclohexylisocyanate), 2,2,4-trimethylhexamethylene diisocyanate, (2-isocyanatoethyl) fumarate, 6-isopropyl-1,3-phenyl diisocyanate, 4-diphenylpropane diisocyanate, lysine diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, tetramethylxylylene diisocyanate, 2,5 ( Alternatively, 2,6) -bis (isocyanatomethyl) -bicyclo [2.2.1] heptane and the like can be mentioned. In particular, 2,4-tolylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, methylene bis (4-cyclohexyl isocyanate) and the like are preferable. These polyisocyanates can be used alone or in combination of two or more.

  (C) Examples of the hydroxyl group-containing (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenyloxypropyl ( (Meth) acrylate, 1,4-butanepolyol mono (meth) acrylate, 2-hydroxyalkyl (meth) acryloyl phosphate, 4-hydroxycyclohexyl (meth) acrylate, 1,6-hexanepolyol mono (meth) acrylate, neopentyl Glycol mono (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolethane di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta Meth) acrylate. Moreover, the compound obtained by addition reaction with glycidyl group containing compounds, such as alkyl glycidyl ether, allyl glycidyl ether, and glycidyl (meth) acrylate, and (meth) acrylic acid can also be used. Of these hydroxyl group-containing (meth) acrylates, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and the like are particularly preferable. These hydroxyl group-containing (meth) acrylate compounds can be used alone or in combination of two or more.

  In the synthesis reaction of the urethane (meth) acrylate as the component (A), for example, copper naphthenate, cobalt naphthenate, zinc naphthenate, dibutyltin dilaurate, triethylamine, 1,4-diazabicyclo [2.2.2] octane. , 2,6,7-trimethyl-1,4-diazabicyclo [2.2.2] octane is preferably used in an amount of 0.01 to 1 part by mass with respect to 100 parts by mass of the total amount of reactants. . The reaction temperature is usually 10 to 90 ° C, particularly preferably 30 to 80 ° C.

  (A) The order of addition of each raw material when synthesizing urethane (meth) acrylate is not particularly limited, but after (b) polyisocyanate and (c) hydroxyl group-containing (meth) acrylate are added, (a1) and / or (A2) It is preferable to add a polyol. By adding each raw material in such an order, compared to the case where the polyol and the polyisocyanate are added first, an oligomer in which the polyol and the polyisocyanate are alternately bonded is less likely to be generated, and the intended (A1), (A2) This is because it becomes easy to obtain a mixture of (A) and (A3).

The urethane (meth) acrylate that is the component (A) is usually blended in an amount of 30 to 80% by mass in total with respect to 100% by mass of the total amount of the composition, from the viewpoint of the mechanical strength of the electric wire coating layer and the coating property. It is particularly preferable that 40 to 70% by mass is blended.
The blending amount of each component of (A1), (A2) and (A3) can be adjusted according to the physical properties of the target wire coating layer. The urethane (meth) acrylate as the component (A1) is usually blended in an amount of 20 to 50% by mass, preferably 22 to 40% by mass, based on 100% by mass of the total amount of the composition. The urethane (meth) acrylate as the component (A2) is usually blended in an amount of 1 to 10% by mass, preferably 2 to 8% by mass, based on 100% by mass of the total amount of the composition. The urethane (meth) acrylate as the component (A3) is usually blended in an amount of 1 to 29% by mass, preferably 10 to 25% by mass, based on 100% by mass of the total amount of the composition.

  The compound having a cyclic structure and one ethylenically unsaturated group as the component (B) is a polymerizable monofunctional compound having a cyclic structure. By using this compound as the component (B), the mechanical properties of the electric wire coating layer obtained from the composition of the present invention are adjusted, and both adhesion to the central conductor and mechanical strength can be achieved. Here, examples of the cyclic structure include an alicyclic structure, a heterocyclic structure containing a nitrogen atom or an oxygen atom, an aromatic ring, and the like, among which an alicyclic structure is particularly preferable.

  Examples of such a polymerizable monofunctional compound (B) having a cyclic structure include isobornyl (meth) acrylate, bornyl (meth) acrylate, tricyclodecanyl (meth) acrylate, and dicyclopentanyl (meth) acrylate. And alicyclic structure-containing (meth) acrylates such as benzyl (meth) acrylate, 4-butylcyclohexyl (meth) acrylate, acryloylmorpholine, vinylimidazole, and vinylpyridine. Furthermore, the compound represented by following formula (1)-(3) can be mentioned.

Wherein R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkylene group having 2 to 8 carbon atoms, preferably 2 to 5 carbon atoms, R ³ represents a hydrogen atom or a methyl group, and p is preferably 1 to 4)

(Wherein R ⁴ , R ⁵ , R ⁶ and R ⁷ are independent of each other and represent a hydrogen atom or a methyl group, and q represents a number of 1 to 5)

  Of these polymerizable monofunctional compounds (B), compounds having a cyclic structure are preferred, and compounds having a crosslinked cyclic structure such as isobornyl (meth) acrylate are particularly preferred. Since the component (B) having a cyclic structure has a rigid structure, the Young's modulus of the cured product is prevented from becoming excessively low, and the balance between the Young's modulus suitable for the wire coating layer, the breaking strength, and the physical properties of breaking elongation is achieved. Can take.

  As commercial products of these polymerizable monofunctional compounds (B), IBXA (manufactured by Osaka Organic Chemical Industry), Aronix M-111, M-113, M114, M-117, TO-1210 (above, manufactured by Toagosei Co., Ltd.) Can be used.

These monofunctional compounds having a cyclic structure as the component (B) are 15 to 60% by mass, and 25 in addition to the total amount of 100% by mass of the composition from the viewpoint of the strength of the wire coating layer and the adhesion to the central conductor. It is preferably blended in an amount of ˜50 mass%, particularly 30 to 50 mass%. However, even in the case of component (B), if a vinyl group-containing lactam such as N-vinylpyrrolidone or N-vinylcaprolactam coexists with the component (D) described later, the storage stability of the composition may be lowered. The total amount of the composition is preferably 5% by mass or less, more preferably 2% by mass, and most preferably not blended at all.
Moreover, it is preferable that (B) component contains isobornyl (meth) acrylate, and it is further that the compounding quantity of isobornyl (meth) acrylate is 50 mass% or more with respect to 100 mass% of whole quantity of (B) component. preferable. By using isobornyl (meth) acrylate, a cured product having excellent mechanical strength can be obtained.

  To the composition of the present invention, (C) a compound having two or more ethylenically unsaturated groups can be blended to the extent that the effects of the invention are not impaired. (C) The compound having two or more ethylenically unsaturated groups is a polymerizable polyfunctional compound. Specific examples of component (C) include, for example, trimethylolpropane tri (meth) acrylate, trimethylolpropane trioxyethyl (meth) acrylate, pentaerythritol tri (meth) acrylate, triethylene glycol diacrylate, tetraethylene glycol di ( (Meth) acrylate, tricyclodecane dimethylol diacrylate, 1,4-butane polyol di (meth) acrylate, 1,6-hexane polyol di (meth) acrylate, neopentyl glycol di (meth) acrylate, tripropylene glycol di ( (Meth) acrylate, neopentyl glycol di (meth) acrylate, bisphenol A diglycidyl ether end (meth) acrylic acid adduct, pentaerythritol tri (meth) acrylate , Pentaerythritol tetra (meth) acrylate, polyester di (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, tris (2-hydroxyethyl) isocyanurate di (meth) acrylate, tricyclodecandi Methylol diacrylate, di (meth) acrylate of polyol of ethylene oxide or propylene oxide adduct of bisphenol A, di (meth) acrylate of polyol of ethylene oxide or propylene oxide adduct of hydrogenated bisphenol A, di (meth) acrylate of bisphenol A Examples include epoxy (meth) acrylate obtained by adding (meth) acrylate to glycidyl ether, and triethylene glycol divinyl ether.

  These (C) compounds having two or more ethylenically unsaturated groups can be blended in an amount of 0 to 5% by mass, more preferably 0 to 2% by mass, based on 100% by mass of the total amount of the composition. Most preferably, it is not blended at all. When it exceeds 5 mass%, the wire coating layer becomes excessively rigid, and the mechanical strength and the adhesion to the center conductor may be impaired.

  (D) component used for the composition of this invention is a compound represented by following formula (4a). By blending the component (D), the adhesion to the central conductor is improved. It is presumed that the component (D) improves the adhesion when the hydroxyl group bonded to the phosphorus atom is coordinated to the metal atom constituting the central conductor and the ethylenically unsaturated group is bonded to the resin matrix. For this reason, in the case of the compound in which all the hydroxyl groups which phosphoric acid has are esterified, since it does not have a hydroxyl group, it is not effective in improving adhesiveness. Moreover, when it replaces with phosphate ester of (D) component and is used as carboxylic acid ester, the effect of adhesive improvement is too small.

(In formula (4a), R ⁸ is a monovalent organic group having an ethylenically unsaturated group, and R ⁹ is a monovalent organic group optionally having a hydrogen atom or an ethylenically unsaturated group. )
The component (D) is preferably a compound represented by the following formula (4).

(In the formula, R represents a hydrogen atom or a methyl group, n is 0 to 1, j is 1 to 2, and k is 3-j).

  Examples of commercially available compounds represented by the above formula (4) include KAYAMER PM-2 and PM-21 (manufactured by Nippon Kayaku Co., Ltd.).

  (D) The compounding quantity of component is 0.01-1 mass% with respect to 100 mass% of composition whole quantity from the point of the adhesiveness with respect to the center conductor of an electric wire coating layer, and intensity | strength, Furthermore, 0.05-0.5 Mass% is preferred.

  (E) A silicone compound can also be mix | blended with the composition of this invention from the point of the adhesiveness with respect to the center conductor of an electric wire coating layer, and a weather resistance. Examples of the silicone compound include polyether-modified silicone, alkyl-modified silicone, urethane acrylate-modified silicone, urethane-modified silicone, methylstyryl-modified silicone, epoxy polyether-modified silicone, and alkylaralkyl polyether-modified silicone.

  Furthermore, (F) a polymerization initiator can be mix | blended with the composition of this invention. (F) As a polymerization initiator, a photoinitiator is preferable. Here, as the photopolymerization initiator, for example, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4'-dimethoxybenzophenone, 4,4'-diaminobenzophenone, Michler's ketone, benzoin propyl ether, benzoin ethyl ether, benzyldimethyl ketal, 1- (4-isopropylphenyl) -2-hydroxy-2- Methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthioxanthone, 2-isopropylthioxanthone, 2 Chlorothioxanthone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis- (2,6-dimethoxybenzoyl) ) -2,4,4-trimethylpentylphosphine oxide; IRGACURE 184, 369, 651, 500, 907, CGI 1700, CGI 1750, CGI 1850, CG 24-61; Darocur 1116, 1173 (above, manufactured by Ciba Specialty Chemicals); Examples include Lucirin TPO (manufactured by BASF); Ubekrill P36 (manufactured by UCB) and the like. Examples of the photosensitizer include triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, 4-dimethylaminobenzoate. Isoamyl acid; Ubekryl P102, 103, 104, 105 (above, manufactured by UCB) and the like.

  (F) It is preferable to mix | blend a polymerization initiator 0.1-10 mass% with respect to 100 mass% of the whole quantity of a composition, especially 0.3-7 mass%.

  In the composition of the present invention, various additives, for example, an antioxidant, a colorant, an ultraviolet absorber, a light stabilizer, a thermal polymerization inhibitor, and a leveling agent, as necessary, within a range not impairing the characteristics of the present invention. , Surfactants, storage stabilizers, plasticizers, lubricants, solvents, fillers, anti-aging agents, wettability improvers, coating surface improvers and the like can be blended.

  The composition of the present invention is cured by radiation. Here, radiation refers to infrared rays, visible rays, ultraviolet rays, X-rays, electron beams, α rays, β rays, γ rays, etc. Is ultraviolet light.

  The viscosity of the composition of the present invention is preferably 0.5 to 10 Pa · s, more preferably 1 to 5 Pa · s at 25 ° C. When the viscosity is within this range, it is easy to apply the wire covering material when manufacturing the electric wire, and the manufacturing efficiency of the electric wire can be improved.

  The Young's modulus of the wire covering layer obtained by curing the composition of the present invention varies depending on the type of the wire covering layer, but in the case of the insulating layer of the covered wire, it is preferably 300 to 1,500 MPa, 400 More preferably, it is -1200 MPa, and it is especially preferable that it is 500-1,000 MPa. When the Young's modulus is within this range, a wire coating layer that is strong against external stress can be obtained.

  The breaking strength and breaking elongation of the electric wire coating layer obtained by curing the composition of the present invention vary depending on the type of the electric wire coating layer, but in the case of the insulating layer of the coated electric wire, the breaking strength is 20 to 60 MPa. It is preferable and it is more preferable that it is 30-50 Mpa. The elongation at break is preferably 80 to 250%, more preferably 90 to 200%. When the breaking strength and breaking elongation are within this range, a highly durable electric wire against external stress can be obtained.

  The composition of the present invention is useful as a radiation curable resin composition for coating electric wires, particularly power wires, telephone wires, and automobile wires. When the composition of the present invention is applied and irradiated with radiation, a uniform and excellent strength electric wire coating layer can be easily formed. Moreover, since the electric wire coating layer formed according to the present invention has excellent strength and good adhesion to the center conductor, the operability of the wiring is good.

  EXAMPLES Next, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these Examples at all.

[Production Example 1: Synthesis of urethane (meth) acrylate as component (A)]
A reaction vessel equipped with a stirrer is charged with 15.38 g of isobornyl acrylate, 0.015 g of 2,6-di-t-butyl-p-cresol, 7.80 g of toluene diisocyanate, and 0.023 g of dibutyltin dilaurate. The solution was ice-cooled while stirring until the liquid temperature reached 20 ° C to 15 ° C. Hydroxyethyl acrylate (6.00 g) was added, and the reaction was performed by stirring for 2 hours while controlling the liquid temperature to be 35 ° C or lower. Next, 28.34 g of polytetramethylene glycol having a number average molecular weight of 2000, 1.79 g of ethylene oxide addition diol of bisphenol A having a number average molecular weight of 400, and 0.022 g of dibutyltin dilaurate are added to the above mixture, and the mixture is stirred for 1 hour at room temperature. After that, it was expanded in an oil bath at 65 ° C. for 2 hours. The reaction was terminated when the residual isocyanate was 0.1% by mass or less. The amount of each raw material used is 5.0 parts by mass of urethane acrylate having a structure represented by the following formula (5), 30.0 parts by mass of urethane acrylate having a structure represented by the following formula (6), and the following: This corresponds to the amount used to obtain 18.0 parts by mass of urethane acrylate having the structure represented by formula (7). Let the obtained (A) urethane acrylate be UA-1. UA-1 is a mixture of urethane acrylates having a structure represented by the following formulas (5) to (7).

HEA-TDI-DA400-TDI-HEA (5)
HEA-TDI-PTMG2000-TDI-HEA (6)
HEA-TDI-HEA (7)
[In the formulas (5) to (7), HEA represents a structure derived from hydroxyethyl acrylate, TDI represents a structure derived from toluene diisocyanate, and DA400 represents ethylene oxide of bisphenol A having a number average molecular weight of 400. The structure derived from addition diol is shown, and PTMG2000 shows the structure derived from polytetramethylene glycol having a number average molecular weight of 2000]

[Comparative Production Example 1: Synthesis of urethane (meth) acrylate not corresponding to component (A)]
A reaction vessel equipped with a stirrer was charged with 0.024 g of 2,6-di-t-butyl-p-cresol, 13.46 g of toluene diisocyanate, and 0.024 g of dibutyltin dilaurate, and the liquid temperature was maintained while stirring them. The solution was ice-cooled until the temperature reached 20 ° C to 15 ° C. 8.98 g of hydroxyethyl acrylate was added, and the reaction was performed by stirring for 2 hours while controlling the liquid temperature to be 35 ° C. or lower. Next, 77.46 g of polytetramethylene glycol having a number average molecular weight of 2000 was added to the above mixture, and the mixture was stirred at room temperature for 1 hour and then expanded in an oil bath at 65 ° C. for 2 hours. The reaction was terminated when the residual isocyanate was 0.1% by mass or less. Let the obtained urethane acrylate be UA-2. UA-2 is a urethane acrylate having a structure represented by the formula (6).

[Comparative Production Example 2: Synthesis of urethane (meth) acrylate not corresponding to component (A)]
In a reaction vessel equipped with a stirrer, 36.92 g of isobornyl acrylate acrylate, 0.015 g of 2,6-di-t-butyl-p-cresol, 11.54 g of toluene diisocyanate, 0.025 g of dibutyltin dilaurate were added. The mixture was stirred and cooled with ice until the liquid temperature reached 20 ° C to 15 ° C while stirring. 7.70 g of hydroxyethyl acrylate was added, and the reaction was performed by stirring for 2 hours while controlling the liquid temperature to be 35 ° C. or lower. Next, 38.15 g of polytetramethylene glycol having a number average molecular weight of 2000, 5.63 g of ethylene oxide-added diol of bisphenol A having a number average molecular weight of 400, and 0.025 g of dibutyltin dilaurate are added to the above mixture, followed by stirring at room temperature for 1 hour. After that, it was expanded in an oil bath at 65 ° C. for 2 hours. The reaction was terminated when the residual isocyanate was 0.1% by mass or less. The amount of each raw material used is to obtain 11.2 parts by mass of the urethane acrylate having the structure represented by the formula (5) and 40.0 parts by mass of the urethane acrylate having the structure represented by the formula (6). It corresponds to the amount of use. Let the obtained urethane (meth) acrylate be UA-3. UA-3 is a mixture of urethane (meth) acrylates having a structure represented by the above formulas (5) to (6).

Examples 1-3 and Comparative Examples 1-5
Each component having the composition shown in Table 1 was charged into a reaction vessel equipped with a stirrer and stirred for 1 hour while controlling the liquid temperature at 50 ° C. to obtain a liquid curable resin composition.

Test Examples The liquid curable resin compositions obtained in the examples and comparative examples were cured by the following method to prepare test pieces, and the following evaluations were performed. The results are also shown in Table 1.

1. Young's modulus:
A liquid curable resin composition was applied on a glass plate using an applicator bar having a thickness of 250 μm, and this was cured by irradiation with ultraviolet rays having an energy of 1 J / cm ² under air to obtain a film for measuring Young's modulus. . A strip-shaped sample was prepared from this film so that the stretched portion had a width of 6 mm and a length of 25 mm, and a tensile test was performed at a temperature of 23 ° C. and a humidity of 50%. The Young's modulus was determined from the tensile strength at 2.5% strain at a pulling speed of 1 mm / min.

2. Breaking strength and breaking elongation:
Using a tensile tester (manufactured by Shimadzu Corporation, AGS-50G), the breaking strength and breaking elongation of the test piece were measured under the following measurement conditions.
Tensile speed: 50 mm / distance between marked lines (measurement distance): 25 mm
Measurement temperature: 23 ° C
Relative humidity: 50% RH

3. Glass transition temperature (Tg):
The resin liquid was applied on a glass plate so as to have a thickness of 200 μm using an applicator, and photocured at a dose of 1.0 J / cm ² to obtain a cured film. A test piece of 3 mm × 35 mm was cut out from this film, and the dynamic viscoelasticity was measured with RHEOVIBRON DDV-01FP manufactured by ORIENTEC. The temperature showing the maximum value of the loss tangent (tan δ) at the vibration frequency of 3.5 Hz was defined as the glass transition temperature, and the glass transition temperature was evaluated.

4). Adhesion to copper and aluminum:
Regarding the compositions obtained in Examples and Comparative Examples, the adhesion of the cured products was measured.
The liquid composition was applied onto a copper plate using an applicator having a thickness of 190 μm, and irradiated with ultraviolet rays of 0.5 J / cm ² under a nitrogen atmosphere to obtain a cured film having a thickness of about 130 μm. This sample was allowed to stand at a temperature of 23 ° C. and a humidity of 50% for 24 hours. Thereafter, a strip-shaped sample was prepared on the copper plate so as to have a width of 10 mm from the cured film. This sample was subjected to an adhesion test in accordance with JIS Z0237 using a tensile tester. The adhesion force with the metal was determined from the tensile strength at a tensile speed of 50 mm / min. Further, the adhesion force when an aluminum plate was used instead of the copper plate was evaluated in the same manner.

In Table 1,
Isobornyl acrylate: IBXA (Osaka Organic Synthesis Co., Ltd.)
Acryloylmorpholine: ACMO (manufactured by Kojinsha)
Lucillin TPO: 2,4,6-trimethylbenzoyldiphenylphosphine oxide (BASF Japan)
Irgacure 184: 1-hydroxycyclohexyl phenyl ketone (Ciba Specialty Chemicals)
Igranox 254: Triethylene glycol bis [3 (3-T-butyl, 4-hydroxy, 5-methylphenyl) propionate] (manufactured by Ciba Specialty Chemicals)
PM-21: a compound in which R = methyl group, n = 1, j = 2, k = 1 in the above formula (4) (KAYAMER PM-21, manufactured by Nippon Kayaku Co., Ltd.)

As is clear from Table 1, the cured product formed of the resin composition of the present invention containing components (A), (B) and (D) has good properties as a wire coating material and is Since the adhesiveness to the conductor is good, it is useful as a wire coating composition.
In Comparative Example 1 containing urethane acrylate not corresponding to component (A) in place of component (A), Young's modulus was too low because UA-2 had a flexible structure. Similarly, in Comparative Example 2 that does not include the component (A), UA-3 does not include the component (A3), and thus is more flexible than the component (A), and the Young's modulus is too low. Since UA-3 has a more rigid structure than UA-2, Comparative Example 2 had a higher Young's modulus value than Comparative Example 1. In Comparative Example 3 not including the component (D), the adhesion to the aluminum plate or the copper plate was reduced. In Comparative Example 4 in which acrylic acid was blended in place of the component (D), the adhesion to the aluminum plate and the copper plate was low, and it was confirmed that acrylic acid could not substitute for the component (D). In Comparative Example 5 in which 2-ethylhexyl acrylate not corresponding to the component (B) was blended in place of the component (B), the Young's modulus decreased.

Claims (8)

The following components (A), (B) and (D);
(A) a mixture of urethane (meth) acrylate having a structure derived from an aliphatic polyol, urethane (meth) acrylate having a structure derived from a cyclic polyol, and urethane (meth) acrylate having no structure derived from a polyol,
(B) a compound having a cyclic structure and one ethylenically unsaturated group,
(D) Compound represented by the following formula (4a)

(In formula (4a), R ⁸ is a monovalent organic group having an ethylenically unsaturated group, and R ⁹ is a monovalent organic group optionally having a hydrogen atom or an ethylenically unsaturated group. )
A radiation curable resin composition for covering electric wires, comprising:   The radiation curable resin composition for wire coating according to claim 1, wherein the component (B) contains isobornyl (meth) acrylate, and the content thereof is 50% by mass or more in the component (B). The radiation curable resin composition for electric wire coating | cover of Claim 1 or 2 whose (D) component is a compound represented by following formula (4).

(In the formula, R represents a hydrogen atom or a methyl group, n is 0 to 1, j is 1 to 2, and k is 3-j).   The radiation curable resin composition for electric wire coating | cover as described in any one of Claims 1-3 whose content of an N-vinyl group containing lactam compound is 5 mass% or less of the whole composition.   (C) The radiation curable resin for electric wire coating according to any one of claims 1 to 4, wherein the content of the compound having two or more ethylenically unsaturated groups is 5% by mass or less of the entire composition. Composition.   The radiation curable resin composition for electric wire coating | cover as described in any one of Claims 1-5 which is an object for insulation layers of an insulated wire.   The electric wire coating layer obtained by hardening the composition of any one of Claims 1-6.   An electric wire having the coating layer according to claim 7.