JP5530313B2 - Thermistor sensor casting resin composition and thermistor sensor - Google Patents

Description

  The present invention relates to a thermistor sensor casting resin composition and a thermistor sensor.

  Thermistor sensors are used in a wide range of fields such as automobiles, home appliances, and industrial equipment as temperature detection elements. As the structure of this thermistor sensor, an electric wire with an insulating coating such as soft vinyl chloride resin is connected to the thermistor element and inserted into a protective case. What is called a resin mold type thermistor sensor in which is injected and cured is known.

  In recent years, the thermistor sensor has been used more severely, while the demand for reliability has been further increased. Resin mold type thermistor sensors are no exception, and thermistor sensors that do not crack in the resin part or cause interfacial delamination between the resin part and the wire even when used under severe conditions such as large temperature differences. Has been requested.

  Therefore, for example, those using a two-part curable polybutadiene urethane resin as the mold resin material, or those having increased adhesion strength to the resin portion of the electric wire by further applying a specific primer on the surface of the insulating coating, etc. It has been developed (for example, see Patent Document 1).

  However, the use of a two-component resin material or a primer leads to a decrease in workability. In particular, the use of a primer increases not only workability but also material costs and manufacturing costs. Further, the mold resin material is required to have a high thermal conductivity in order to quickly transmit a temperature change to the thermistor element, but in this respect as well, the thermistor sensor has a slightly insufficient characteristic.

JP-A-8-94452

  The present invention has been made to solve the above-mentioned problems of the prior art, and itself forms a resin portion that has high thermal conductivity and that does not cause cracks or interfacial peeling without being subjected to a primer treatment. It is an object to provide a thermistor sensor casting resin composition that can be used, and a thermistor sensor that has high performance and high reliability using such a composition.

  The resin composition for casting the thermistor sensor according to one embodiment of the present invention includes (A) 100 parts by mass of a bisphenol A type epoxy resin, (B) 2 to 20 parts by mass of a flexible epoxy resin, and (C) a reactive diluent. It contains 2 to 20 parts by mass, (D) 80 to 200 parts by mass of an amine-based curing agent, and (E) 300 to 500 parts by mass of alumina powder.

  A thermistor sensor according to another aspect of the present invention includes a thermistor element, an insulated wire connected to the thermistor element, and a resin portion formed by casting on the outer periphery of the thermistor element and the insulated wire, The resin part is made of the thermistor sensor casting resin composition.

  According to the present invention, it is possible to manufacture a thermistor sensor having high performance and high reliability at a lower cost and with better workability than the conventional one.

It is sectional drawing which shows schematic structure of the thermistor sensor of one Embodiment of this invention. It is sectional drawing explaining the characteristic evaluation method of the resin composition for thermistor sensor casting.

Hereinafter, the present invention will be described in detail.
First, each component used for the thermistor sensor casting resin composition of the present invention will be described.

（式中、ｎは０または１以上の整数を表す） The component (A) bisphenol A type epoxy resin used in the present invention is a liquid epoxy resin represented by the following general formula (1), and is obtained by a condensation reaction of bisphenol A and an epihalohydrin such as epichlorohydrin. As a commercial item, R-140 (Mitsui Chemicals make brand name) etc. are mentioned, for example.

(In the formula, n represents 0 or an integer of 1 or more)

  Next, the flexible epoxy resin (B) used in the present invention is a bisphenol A type epoxy resin modified with an aliphatic polyether. Specifically, for example, the main chain of the bisphenol A type epoxy resin has an ethyleneoxyethyl group, a di (ethyleneoxy) ethyl group, a tri (ethyleneoxy) ethyl group, a propyleneoxypropyl group, a di (propyleneoxy) propyl group. Having a flexible skeleton such as a tri (propyleneoxy) propyl group, an alkylene group having 2 to 15 carbon atoms, and a polar skeleton represented by the following general formula (2), for example, the following general formulas (3) to ( For example, those represented by the following general formula (6) obtained by epoxidizing a polyol obtained by adding an alkylene oxide such as ethylene oxide or propylene oxide to bisphenol A are used. Note that the flexible skeleton may have an alkyl group having 1 to 4 carbon atoms. Examples of commercially available products include Adeka Resin EP-4000, Adeka Resin EP-4003 (all are trade names manufactured by ADEKA), EPICLON EXA-4850-150 (trade names manufactured by DIC Corporation), and the like. As the flexible epoxy resin of component (B), among them, those having a vinyl ether skeleton, for example, EPICLON EXA-4850-150 (trade name) and the like are preferable. By using a flexible epoxy resin having such a vinyl ether skeleton, the adhesive force to a protective case made of a copper tube or the like is improved.

（式中、ｎは１〜１０の整数を表す）

(In the formula, n represents an integer of 1 to 10)

（式中、Ｒは水素原子またはメチル基、ｍ及びｎは、ｍ≧０、ｎ≧０、及びｍ＋ｎ＝２を満足する整数を表す）

(In the formula, R represents a hydrogen atom or a methyl group, and m and n represent integers satisfying m ≧ 0, n ≧ 0, and m + n = 2).

  The blending amount of the flexible epoxy resin as the component (B) is preferably in the range of 2 to 20 parts by mass with respect to 100 parts by mass of the bisphenol A type epoxy resin of the component (A), and in the range of 4 to 10 parts by mass. More preferred. If the blending amount is less than 2 parts by mass, the adhesive strength to a protective case made of a copper tube or the like may be reduced. Conversely, if it exceeds 20 parts by mass, the moisture resistance of the cured product may be reduced.

  In addition to the above components (A) and (B), other epoxy resins can be used in combination. Epoxy resins used in combination include epoxidized phenol and aldehyde novolak resins such as phenol novolac type epoxy resin and cresol novolak type epoxy resin; diglycidyl ethers such as bisphenol F, bisphenol S and alkyl-substituted bisphenol, diamino Glycidylamine epoxy resin obtained by reaction of polyamines such as diphenylmethane and isocyanuric acid with epichlorohydrin; linear aliphatic epoxy resin obtained by oxidizing olefinic bonds with peracids such as peracetic acid; obtained by epoxidation of cyclohexane derivatives, etc. Alicyclic epoxy resin; biphenyl type epoxy resin and the like. These epoxy resins may be used individually by 1 type, and 2 or more types may be mixed and used for them. When another epoxy resin is used in combination, it is preferably 25% by mass or less, more preferably 20% by mass or less, based on the total amount of the epoxy resin, from the viewpoint of adhesion and moisture resistance.

  Next, as the reactive diluent of the component (C) used in the present invention, for example, butyl glycidyl ether, polypropylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, butanediol diglycidyl ether, 1,6-hexanediol Examples thereof include diglycidyl ether and dodecyl glycidyl ether. Among these, glycidyl ethers of higher alcohols having 6 or more carbon atoms such as 1,6-hexanediol diglycidyl ether and dodecyl glycidyl ether are preferable from the viewpoint of imparting flexibility. Examples of such commercially available products of higher alcohol glycidyl ether include SY40M, SY35M (all of which are trade names manufactured by Sakamoto Pharmaceutical Co., Ltd.). A reactive diluent may be used individually by 1 type, and 2 or more types may be mixed and used for it.

  The compounding amount of the reactive diluent of component (C) is preferably in the range of 2 to 20 parts by mass with respect to 100 parts by mass of the bisphenol A type epoxy resin of component (A), and more preferably in the range of 4 to 10 parts by mass. preferable. If the blending amount is less than 2 parts by mass, the dilution effect may not be sufficiently obtained. Conversely, if it exceeds 20 parts by mass, the reactivity may be poor.

  Next, as the amine-based curing agent of the component (D) used in the present invention, 2 to 80 carbon atoms such as polyetheramine, ethylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine and the like. Aliphatic polyamines of p-xylenediamine, m-xylenediamine, 1,5-diaminonaphthalene, m-phenylenediamine, p-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylethane 4,4′-diaminodiphenylpropane, 4,4′-diaminodiphenyl ether, 1,1-bis (4-aminophenyl) cyclohexane, 4,4′-diaminodiphenylsulfone, bis (4-aminophenyl) phenylmethane, etc. Aromatic polyamines 4,4'-diaminodiphenyl cyclohexane, 1,3-bis alicyclic polyvalent amines such as (aminomethyl) cyclohexane; dicyandiamide, and the like. Among these, aliphatic polyvalent amines are preferable from the viewpoint of long life, and polyether amines are more preferable. An amine hardening | curing agent may be used individually by 1 type, and 2 or more types may be mixed and used for it.

  The compounding amount of the (D) component amine curing agent may be any amount that can cure the (A) and (B) component epoxy resins, but preferably the (A) component bisphenol A type epoxy. It is the range of 80-200 mass parts with respect to 100 mass parts of resin, and it is more preferable in it being the range of 80-180 mass parts. If the blending amount is less than 80 parts by mass, the glass transition point of the cured product is lowered. Conversely, if it exceeds 200 parts by mass, the moisture resistance of the cured product may be reduced.

In addition to the component (D), other curing agents such as a phenolic curing agent and an acid anhydride curing agent can be used in combination. Examples of phenolic curing agents include aralkyl type phenol resins such as phenol aralkyl resins and naphthol aralkyl resins, novolak type phenol resins such as phenol novolak resins and cresol novolak resins, and modified resins thereof such as epoxidized or butylated novolaks. Type phenolic resin, dicyclopentadiene modified phenolic resin, paraxylene modified phenolic resin, triphenolalkane type phenolic resin, polyfunctional phenolic resin and the like. Examples of the acid anhydride curing agent include hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methyl hymic anhydride, and derivatives thereof. In addition, Lewis acid amine complexes such as dicyanamide, imidazole, aluminum chelate, and BF ₃ can also be used. These may be used individually by 1 type, and 2 or more types may be mixed and used for them. When other curing agents are used in combination, it is preferably 20% by mass or less, more preferably 10% by mass or less, based on the total amount of the curing agent, from the viewpoint of curability and crosslinkability.

  Furthermore, the hardening accelerator which accelerates | stimulates reaction with an epoxy resin and a hardening | curing agent can also be mix | blended in the range which does not inhibit the hardening of this invention. Examples of the curing accelerator include 2-ethyl-4-methylimidazole, 2-heptadecylimidazole, 2-methylimidazole, 2-ethylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, and 4-methyl. Imidazole, 4-ethylimidazole, 2-phenyl-4-hydroxymethylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxy Imidazole compounds such as methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole; triethylamine, triethylenediamine, benzyldimethylamine, α-methylbenzyldimethylamine, triethanolamine, dimethylamino Tertiary amines such as ethanol, 2- (dimethylaminomethyl) phenol, tris (dimethylaminomethyl) phenol, 1,8-diazabicyclo [5,4,0] undecene-7 (DBU), 1,5-diazabicyclo [ 4,3,0] nonene-5 and other diazabicycloalkenes and derivatives thereof, and phosphines such as triethylphosphine, triphenylphosphine and diphenylphosphine.

  Next, the alumina powder of the component (E) used in the present invention preferably has a number average particle size of 2 to 15 μm, and more preferably 4 to 12 μm. When the number average particle size is less than 2 μm, the viscosity of the composition increases, and when the number average particle size exceeds 15 μm, the composition tends to settle.

  The blending amount of the alumina powder of the component (E) is preferably in the range of 300 to 500 parts by weight, more preferably in the range of 300 to 350 parts by weight with respect to 100 parts by weight of the bisphenol A type epoxy resin of the component (A). preferable. When the blending amount is less than 300 parts by mass, the thermal conductivity of the cured product decreases, and conversely when it exceeds 500 parts by mass, the viscosity of the composition increases.

  In the resin composition for casting the thermistor sensor of the present invention, one or more inorganic fillers other than the alumina powder of the component (E) can be blended as necessary as long as the effects of the present invention are not impaired. . Examples of such inorganic fillers include, for example, silica, zircon, talc, calcium silicate, calcium carbonate, titanium white, clay, bengara, silicon carbide, boron nitride, beryllia, zirconia, and the like. Examples include potassium titanate, silicon carbide, and silicon nitride.

  Further, in the resin composition for casting the thermistor sensor of the present invention, in addition to the above-mentioned components, a coupling generally blended in this type of composition as necessary as long as the effects of the present invention are not impaired. A flame retardant such as a colorant such as an agent, an anti-settling agent and carbon black, an antifoaming agent, and antimony trioxide can be blended.

  In the resin composition for casting the thermistor sensor of the present invention, the cured product obtained by curing at 100 ° C. for 6 hours preferably has a thermal conductivity of 0.7 W / (m · K) or more, 0.9 W / More preferably (m · K) or more. When the thermal conductivity is less than 0.7 W / (m · K), the sensitivity of the sensor decreases. The thermal conductivity is measured by a probe method.

  The thermistor sensor casting resin composition of the present invention is a one-pack type thermistor sensor by uniformly mixing each component of (A) to (E) and other components described above with a mixer or the like. It can be obtained as a resin composition for casting. In addition, a two-pack type thermistor sensor which includes a component (D) and a curing agent containing other curing agents and a curing accelerator blended as necessary, and a main agent containing components other than these curing agent components. It can also be prepared as a molding resin composition. The main agent and the curing agent are uniformly mixed by a mixer or the like when used.

Next, the thermistor sensor of the present invention will be described.
The thermistor sensor of the present invention is obtained by cast-curing the above thermistor sensor casting resin composition, and FIG. 1 shows an embodiment thereof. Note that the drawings are provided for illustration only, and the present invention is not limited to these drawings.

  As shown in FIG. 1, the thermistor sensor 10 of this embodiment includes a thermistor element 11, a lead wire 12 made of a copper wire or the like connected to the thermistor element 11, and an external lead connected via the lead wire 12. The end portion of the wire 13 is inserted into a protective case (copper tube) 14, and the resin portion 15 is formed by injecting and curing a liquid resin composition into the protective case 14. The external lead wire 13 is composed of an insulated wire in which the outer periphery of the conductor 13a is provided with an insulating coating 13b such as soft vinyl chloride resin or cross-linked polyethylene. Further, as the liquid resin composition forming the resin portion 15, the external lead wire 13 is described above. The thermistor sensor casting resin composition is used.

  In manufacturing the thermistor sensor 10 of the present embodiment, the thermistor element 11 to which the lead wire 12 and the external lead wire 13 are connected is inserted into the protective case 14 in which the thermistor sensor casting resin composition is previously injected, and thereafter The thermistor sensor casting resin composition may be cured, or the thermistor sensor casting resin connected to the lead wire 12 and the external lead wire 13 is inserted into the protective case 14, and then the thermistor sensor casting resin. The composition may be injected and cured. As curing conditions, a temperature of 95 to 105 ° C. is preferably about 5 to 7 hours.

  In the thermistor sensor 10 of the present embodiment, the resin composition for casting the thermistor described above is used, so that cracks and interface peeling do not occur in the resin part even in use under severe environments, and the long-term It is possible to have high reliability over a wide range. In addition, since there is no need for a primer treatment on the surface of the insulating coating 13b as in the prior art, workability is good, and material costs and manufacturing costs are reduced. Furthermore, since the thermistor sensor casting resin composition has a high thermal conductivity, an external temperature change can be quickly transmitted to the thermistor element, thereby having a high sensor function.

  The adhesion of the thermistor sensor casting resin composition to the insulating coating 13b is particularly good when the insulating coating 13b is made of a soft vinyl chloride resin. Therefore, the present invention provides a particularly remarkable effect when applied to a thermistor sensor using an electric wire whose insulating coating 13b is made of a soft vinyl chloride resin.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples at all. In the following description, “parts” means “parts by mass” unless otherwise specified.

Example 1
90 parts of bisphenol A type epoxy resin (trade name R140P manufactured by Mitsui Chemicals, Inc .; expressed as epoxy resin (1)), vinyl ether-modified epoxy resin (trade name manufactured by DIC Corporation EPICLON EXA4850-150; epoxy resin (2) 5 parts, higher alcohol glycidyl ether (trade name SY40M manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.) as a reactive diluent, carbon black having an average particle size of 0.024 μm (trade name MA100R manufactured by Mitsubishi Chemical Corporation) 1 .2 parts, 140 parts of alumina powder having an average particle size of 4 μm (trade name LA4000 manufactured by Taiheiyo Random Co., Ltd.), 180 parts of alumina powder having an average particle size of 12 μm (trade name LA1200 manufactured by Taiheiyo Random Co., Ltd.), an antifoaming agent ( Product name TSA720 manufactured by Momentive Performance Materials Japan 0. Part, anti-settling agent (trade name: S-Ben, manufactured by Nippon Organoclay Co., Ltd.), polyetheramine having a molecular weight of 430 (trade name: Jeffamine D-400, manufactured by Huntsman Corp .; expressed as curing agent (1)) 19.4 Parts and a polyetheramine having a molecular weight of 2000 (trade name: Jeffamine D-2000 manufactured by Huntsman Corp .; expressed as a curing agent (2)) by vacuum kneading to prepare an epoxy resin composition, as shown in FIG. A thermistor sensor was manufactured by injecting into a protective case 14 made of copper in which the thermistor element 11, lead 12 wire and the like were previously set, and heating and curing at 100 ° C. for 6 hours.

(Example 2)
The epoxy resin composition was the same as in Example 1 except that butyl glycidyl ether (trade name BGE manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.) was used as the reactive diluent instead of higher alcohol glycidyl ether (trade name SY40M). Further, a thermistor sensor was manufactured using this composition.

(Example 3)
Epoxy resin composition in the same manner as in Example 1 except that the blending amounts of alumina powder having an average particle size of 4 μm (trade name LA4000) and alumina powder having an average particle size of 12 μm (trade name LA1200) were changed to 200 parts and 120 parts, respectively. The thermistor sensor was manufactured using this composition.

Example 4
The blending amounts of alumina powder (trade name LA4000) having an average particle diameter of 4 μm and alumina powder (trade name LA1200) having an average particle diameter of 12 μm were changed to 157 parts and 202 parts, respectively, and a polyetheramine having a molecular weight of 2000 as a curing agent component ( An epoxy resin composition was prepared in the same manner as in Example 1 except that 160 parts of the product name “Jefamine D-2000” was added alone, and a thermistor sensor was produced using this composition.

(Example 5)
Instead of vinyl ether-modified epoxy resin (trade name EPICRON EXA4850-150), diglycidyl ether of bisphenol A-alkylene oxide adduct (trade name EP-4000 manufactured by ADEKA Co., Ltd .; expressed as epoxy resin (3)) was used. Except for the above, an epoxy resin composition was prepared in the same manner as in Example 1, and a thermistor sensor was produced using this composition.

(Comparative Example 1)
Example 1 except that the blending amount of bisphenol A type epoxy resin (trade name R140P) is 95 parts and a mixture of vinyl ether-modified aliphatic epoxy resin and bisphenol A (trade name EPICRON EXA4850-150) is not blended. Similarly, an epoxy resin composition was prepared, and a thermistor sensor was manufactured using this composition.

(Comparative Example 2)
An epoxy resin composition was prepared in the same manner as in Example 1 except that the total amount of the alumina powder was changed to silica powder having an average particle size of 6.6 μm (trade name CMC-12S manufactured by Tatsumori Co., Ltd.). A thermistor sensor was manufactured using this composition.

(Comparative Example 3)
The blending amounts of alumina powder (trade name LA4000) having an average particle diameter of 4 μm and alumina powder (trade name LA1200) having an average particle diameter of 12 μm are 136.5 parts and 175.5 parts, respectively, and methyltetrahydroanhydride phthalate as a curing agent component. The same as in Example 1 except that 82.4 parts of acid (trade name HN2000, manufactured by Hitachi Chemical Co., Ltd.) and 1.6 parts of curing accelerator (trade name: Kao Riser No. 20, manufactured by Kao Corporation) were used. Then, an epoxy resin composition was prepared, and a thermistor sensor was manufactured using this composition.

(Comparative Example 4)
An epoxy resin composition was prepared in the same manner as in Example 1 except that no reactive diluent was used, and a thermistor sensor was produced using this composition.

  About the epoxy resin composition and the thermistor sensor obtained by said each Example and comparative example, various characteristics were evaluated by the method as shown below. The results are shown in Table 1 together with the composition of the resin composition.

[viscosity]
The viscosity of the epoxy resin composition immediately after preparation was measured using a B-type viscometer under the conditions of 25 ° C. and 12 rpm.
[Curing property]
The epoxy resin composition was put in a test tube, and the wire was moved up and down at a rate of once per second at 140 ° C., and the time until the wire no longer sunk was measured.
[Hardness]
A sample (50 g) prepared by curing the epoxy resin composition at 100 ° C. for 6 hours was measured at 25 ° C. using a type C2 durometer.
[Insulated wire peel strength]
An epoxy resin composition was applied to a copper plate over a length of 5 cm, and φ1.5 mm × 2 parallel vinyl chloride resin insulated wires were placed thereon, and the epoxy resin composition was heated and cured at 100 ° C. for 6 hours. Thereafter, a 180 ° peel test was performed using an autograph manufactured by Shimadzu Corporation.
[Insulated wire pull-out strength]
As shown in FIG. 2, an epoxy resin composition 23 is injected into a copper case 21 together with φ1.5 mm × 2 parallel vinyl chloride resin insulated wires 22 and cured under conditions of 100 ° C. for 6 hours. Sample 24 was prepared. With respect to this sample, the pulling force of the vinyl chloride resin insulated wire 22 was measured using a push-pull gauge manufactured by Imada Corporation.
[Thermal conductivity]
A sample prepared by curing the epoxy resin composition at 100 ° C. for 6 hours was measured using a heat conductivity meter manufactured by Kyoto Electronics Industry Co., Ltd.
[Thermistor sensor reliability]
The thermistor sensor was subjected to a cycle test in the air at −25 ° C. to 75 ° C., and the occurrence of cracks in the cross section of the resin part after 500 cycles was visually observed to examine the occurrence rate (number of samples: 10).
[Injection workability]
Workability at the time of injection of the epoxy resin composition (using a 1.20 × 38 mm injection needle manufactured by Terumo Corporation) was evaluated according to the following criteria.
○ ... casting time less than 30 seconds △ ... casting time 30 seconds or more and less than 60 seconds × ... casting time 60 seconds or more

 These results are shown in Table 1 together with the composition of the epoxy resin composition.

  As is apparent from Table 1, all the thermistor sensors obtained in the examples had high reliability and good workability.

  DESCRIPTION OF SYMBOLS 10 ... Thermistor sensor, 11 ... Thermistor element, 12 ... Lead wire, 13 ... External lead wire which consists of insulated wires, 14 ... Protective case, 15 ... Resin part.

Claims (7)

  (A) 100 parts by mass of bisphenol A type epoxy resin, (B) 2 to 20 parts by mass of flexible epoxy resin, (C) 2 to 20 parts by mass of reactive diluent, (D) 80 to 200 parts by mass of amine-based curing agent And (E) 300 to 500 parts by mass of alumina powder, and a thermistor sensor casting resin composition.   (B) The thermistor sensor casting resin composition according to claim 1, wherein the flexible epoxy resin is a modified epoxy resin obtained by modifying a bisphenol A type epoxy resin with an aliphatic polyether.  The thermistor sensor casting resin composition according to claim 2, wherein the modified epoxy resin has a vinyl ether skeleton.   (C) The reactive diluent is a higher alcohol glycidyl ether having 12 to 14 carbon atoms, The thermistor sensor casting resin composition according to any one of claims 1 to 3.  The thermistor sensorNote according to any one of claims 1 to 4, wherein the cured product has a thermal conductivity of 0.7 W / (m · K) or more when cured at 100 ° C for 6 hours. Forming resin composition.   6. The thermistor sensor casting resin composition according to any one of claims 1 to 5, which is a one-component casting resin composition. A thermistor element, an insulated wire connected to the thermistor element, and a resin portion formed by casting on the outer periphery of the thermistor element and the insulated wire,
The thermistor sensor, wherein the resin part is made of the resin composition for casting the thermistor sensor according to any one of claims 1 to 6.

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