JP2004277635A - Phenolic resin molding material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a phenolic resin material for molding, causing little adhesion of soldering during soldering dip treatment at around 500°C, gives a molded product of a fine appearance with reduced corrosion of electric contacting points by ammonia gas, and also to provide a transformer bobbin molded from the above material. <P>SOLUTION: The phenolic resin material for molding comprises: (a) a novolac type phenolic resin and hexamethylenetetramine; (b) ferrous sulfate; and (c) zeolite. These components are preferably mixed in the proportions of 30-60 wt.% of (a), 2-15 wt.% of (b) and 10-30 wt.% of (c) to the whole amount of the molding material. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００２５】
２．トランスボビンの成形
実施例及び比較例で得られた成形材料を、下記の条件で成形し、トランスボビンを得た。
（１）成形機 東芝製 ＩＲ−１００
（２）金型温度 １７５℃
（３）シリンダー温度 先端９０℃／後４５℃
（４）射出圧力、速度 充填時間２秒間になるように設定
（５）硬化時間 ２０秒
（６）射出量 ２０ｇ／１ショット
（７）取り数 １４ヶ／１ショット
（８）成形体形状 ツバ部１２×１３ｍｍ 高さ１５ｍｍのコイルボビン
【００２６】
３．評価
上記方法で得られたトランスボビンについて、特性評価を行った。その結果を表２に示す。
【表２】

【００２７】
４．評価方法
（１）高温ハンダ特性
このトランスボビンを５００℃のハンダ槽に５秒間ディップ処理して、ディップ処理面のフクレ、クラック、反りの発生状況を目視で判定した。
（２）ウレタン被膜絶縁特性保持率（発生ガスの影響による）
実施例及び比較例で得られた成形材料を、上記に準じた射出成形法（但し、取り数は３コ／１ショットである）により成形し、１２．７ｍｍ×１ｍｍ×１２７ｍｍの成形体（テストピース）を得た。
容器に、ウレタン被膜された電線２本を撚ったものと、上記テストピース３枚を入れて密閉した。これを１５０℃で２週間放置後、２本の電線間の絶縁破壊強さを、ＪＩＳ Ｋ ６９１１で規定された「短時間法」に従って昇圧して測定し、処理前の絶縁破壊強さに対する保持率を算出した。
【００２８】
実施例１は、無機基材として硫酸第一鉄、ゼオライト、焼成クレー、有機基材として木粉を用い、実施例２は、無機基材として硫酸第一鉄、ゼオライト、焼成クレーを使用し、有機基材は使用していない。この結果、５００℃ハンダ浸漬処理後の外観はいずれも良好であり、ウレタン被膜の絶縁特性保持率も高かった。一方、比較例１〜３は、硫酸第一鉄、ゼオライトいずれかまたは両方を用いておらず、ハンダ浸漬処理後の成形体にクラックが多く発生した。また、ウレタン被膜の絶縁特性の低下も著しかった。
【００２９】
【発明の効果】
本発明は、ノボラック型フェノール樹脂とヘキサメチレンテトラミンを使用したフェノール樹脂成形材料において、硫酸第一鉄およびゼオライトを使用することにより、腐食性ガスの吸収効果、特にアンモニアガスの捕捉を図ったものであり、本発明の成形材料を用いて得られたトランスボビン成形体は、５００℃近辺におけるハンダディップ処理を行っても外観にフクレ、クラック等の異常が無く、かつ電気的接点の腐食を生じることがない。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a phenolic resin molding material and a trans bobbin formed by molding the same.
[0002]
[Prior art]
Transformers are used in all kinds of electrical products, but in recent years the market has been rapidly expanding with the spread of personal computers and mobile phones. 2. Description of the Related Art Relatively large transformers are used in home appliances such as televisions, and molding materials such as phenol resin, PET (polyethylene terephthalate), and PBT (polybutylene terephthalate) are used as bobbin materials. In a group of products using transformers formed into chips, such as communication equipment, a molding material of phenol resin, LCP (fully aromatic polyester resin, commonly known as liquid crystal polymer), or the like is used as a bobbin material. Here, the phenolic resin is characterized by heat resistance and low warpage, and the PET, PBT, and LCP are characterized by having excellent bobbin brim strength.
[0003]
Originally, a molded article of a phenolic resin, which is a thermosetting resin, is widely used from a large trans bobbin to a chip bobbin because it is excellent in heat resistance, dimensional accuracy, and hardly deforms such as warpage. In the process of manufacturing the transformer, there is a "solder dip" process of melting the winding film and soldering it to the pin of the bobbin. In the case of resins such as PET, PBT, and LCP, the appearance is greatly deteriorated because the resin is melted. Therefore, there is a background that the phenol resin has been suitably used in this application.
[0004]
However, even when phenolic resin is used, depending on the composition of the molding material, gas is generated from the inside of the molded body during the solder dip process, which lowers the smoothness of the molded body surface, so that the solder adheres to the molded body surface. However, there is a problem that man-hours are required for finishing the molded body.
Phenolic resins are generally classified into novolak resins and resol resins, but novolak resins use hexamethylenetetramine as a curing agent, which decomposes and becomes a source of ammonia gas, causing corrosion of electrical contacts. It is difficult to apply to electronic parts due to problems such as Therefore, resol resins have been used in these applications, although novolak resins are more cost-effective.
[0005]
On the other hand, according to the knowledge of the present inventor, when ferrous sulfate or zeolite is used alone in the phenolic resin molding material, the solder dipability can be improved and the deterioration of the wire coating can be reduced. However, in this case, it was necessary to use a plant fiber, a crushed product thereof or a crushed plant husk in combination.
[0006]
Further, with respect to zeolites, it is described in Patent Documents 1 and 2 below that a metal-containing zeolite such as silver is used as an antibacterial agent in a phenolic resin molding material. It is not known to absorb the gas generated from the compact. On the other hand, a composition in which an iron compound is blended with a phenol resin is described in, for example, Patent Document 3. This is to prevent the odor generated from the phenol resin by using an iron compound and a copper compound in combination.
[0007]
[Patent Document 1]
JP-A-7-109404 [Patent Document 2]
JP-A-10-226755 [Patent Document 3]
JP-A-6-63110
[Problems to be solved by the invention]
The present invention relates to a phenolic resin molding material using a novolak type phenolic resin and hexamethylenetetramine, has a good appearance with little solder adhesion even in a solder dip treatment at around 500 ° C., and corrosion of electrical contacts by ammonia gas. It is intended to provide a phenolic resin molding material capable of molding a molded body capable of reducing the amount of phenol resin, and a trans bobbin formed by molding the same.
[0009]
[Means for Solving the Problems]
Such an object is achieved by the following present inventions (1) to (3).
(1) A phenolic resin molding material comprising (a) a novolak type phenolic resin and hexamethylenetetramine, (b) ferrous sulfate, and (c) zeolite.
(2) For the entire molding material,
(A) a total of 30 to 60% by weight of a novolak-type phenol resin and hexamethylenetetramine;
(B) 2 to 15% by weight of ferrous sulfate;
(C) 10 to 30% by weight of zeolite
The phenolic resin molding material according to the above (1), comprising:
(3) A trans bobbin formed by molding the molding material according to any one of (1) and (2).
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the phenolic resin molding material and the trans bobbin of the present invention will be described.
The phenolic resin molding material of the present invention (hereinafter sometimes simply referred to as “molding material”) contains (a) a novolak-type phenolic resin, hexamethylenetetramine, (b) ferrous sulfate, and (c) zeolite. It is characterized by the following. The trans bobbin of the present invention is obtained by molding the molding material of the present invention.
[0011]
First, the molding material of the present invention will be described.
The phenol resin used in the molding material of the present invention is a novolak type phenol resin. The novolak-type phenol resin is not particularly limited, but is obtained by reacting a phenol and an aldehyde in the presence of an acidic catalyst, and its properties are not particularly limited.
The novolak-type phenol resin used in the molding material of the present invention contains hexamethylenetetramine as a curing agent in the same manner as usual. The blending amount of hexamethylenetetramine is not particularly limited, but is preferably 10 to 25 parts by weight based on 100 parts by weight of the novolak type phenol resin. In addition, a resol type phenol resin can be used as a part of the phenol resin. The amount is usually not more than 30% by weight of the whole phenolic resin.
[0012]
The compounding amount of the novolak type phenol resin used in the molding material of the present invention is not particularly limited, but the total amount of the novolak type phenol resin and hexamethylenetetramine may be 30 to 60% by weight based on the whole molding material. preferable. More preferably, it is 40 to 55% by weight. Thereby, good fluidity can be imparted to the molding material. If the content is less than the lower limit, the moldability may be reduced due to low fluidity, and if the content is more than the upper limit, the molding material may have low viscosity and may be difficult to mold.
[0013]
The molding material of the present invention contains hexamethylenetetramine as a curing agent for the novolak-type phenol resin. In addition, if necessary, magnesium oxide or calcium hydroxide may be added as a curing aid to the novolak-type phenol resin in an amount of 100% by weight. 15 parts by weight or less can be used. In addition, since calcium hydroxide decomposes at 500 ° C. or lower, it is preferable that the added amount be as small as possible.
[0014]
The molding material of the present invention is characterized by blending ferrous sulfate and zeolite. Thereby, the gas absorption effect can be imparted while maintaining the heat resistance and mechanical strength of the molded body.
The ferrous sulfate used in the present invention has a very high ammonia trapping performance because sulfate ions form salts with corrosive gases such as ammonia, and divalent iron ions also form amine complex salts with ammonia. are doing. Although ferrous sulfate has a different hydration number such as monohydrate and heptahydrate, any of them can be used in the molding material of the present invention and is not particularly limited.
[0015]
The zeolite used in the present invention is a metal salt of silicic acid / aluminic acid and has adsorbed water, and such a structure has a cation exchange property. These characteristics are factors that develop the property of absorbing a polar gas. By utilizing this property, the reaction gas generated at a high temperature can be absorbed by the molded body, and the appearance of the surface of the molded body can be prevented from deteriorating. Further, by adsorbing the ammonia gas, corrosion of the metal or plastic insulator caused by the ammonia gas can be prevented. Although zeolite includes a synthetic product synthesized by a chemical reaction with a natural product, any of them can be used in the molding material of the present invention, and there is no particular limitation.
By utilizing these properties of ferrous sulfate and zeolite, corrosive gases generated at high temperatures, especially ammonia gas, can be captured to prevent corrosion of metals and plastic insulators caused by these corrosive gases. In addition, it is possible to prevent the appearance from cracking.
[0016]
The compounding amount of ferrous sulfate and zeolite in the molding material of the present invention is not particularly limited, but ferrous sulfate is preferably blended in an amount of 2 to 15% by weight based on the whole molding material, and more preferably 5 to 5% by weight. 10% by weight. The zeolite is preferably blended in an amount of 10 to 30% by weight, more preferably 20 to 25% by weight, based on the whole molding material. Thereby, the moldability of the molding material can be maintained, and a sufficient gas absorbing effect can be imparted. Ferrous sulfate and zeolite alone can improve the solder dip resistance due to the gas adsorption effect, but the effect is small even if the compounding amount is increased, and the specific organic fiber with high gas adsorption effect can be used alone. Must be used together. Further, when the addition amount is increased, ferrous sulfate causes a decrease in insulating properties, and zeolite causes a decrease in fluidity of a molding material due to thickening. By using both of them, corrosion of metal or plastic insulator can be prevented, and occurrence of cracks in appearance can be prevented. In addition, since the effect of improving solder dip can be obtained without using an organic base material, a material having high dimensional stability can be obtained in combination with another inorganic base material.
[0017]
If the amount of zeolite is less than the above lower limit, the effect of compounding may not be sufficient, and if the molded body is treated at a high temperature such as solder dip, blisters and cracks may occur in appearance. On the other hand, when the amount is larger than the upper limit, the fluidity during molding of the molding material may be reduced. If the amount of ferrous sulfate is less than the lower limit, the effect of the compounding may not be sufficient, and if the molded body is treated at a high temperature such as solder dip, blisters and cracks may occur in the appearance. On the other hand, if it is larger than the upper limit, the insulation resistance of the cured product during humidification may be reduced.
[0018]
The molding material of the present invention may contain an inorganic base material in addition to the above ferrous sulfate and zeolite. Thereby, heat resistance and dimensional accuracy can be improved. The inorganic base material other than ferrous sulfate and zeolite is not particularly limited, but examples thereof include glass fiber, calcium carbonate, calcined clay, talc, silica, diatomaceous earth, alumina, magnesium oxide, aluminum hydroxide, magnesium hydroxide, and magnesium hydroxide. Calcined clay and the like. These can be used alone or in combination of two or more. The amount of the inorganic substrate is not particularly limited, but is preferably 15 to 45% by weight, particularly 20 to 35% by weight based on the entire molding material, from the viewpoint of heat resistance, improvement of dimensional accuracy, and moldability. Is preferred.
Here, inorganic substrates having crystallization water at 500 ° C. or less, such as aluminum hydroxide, magnesium hydroxide, and unfired clay, dissociate water at the time of solder dip treatment, which may cause deterioration in appearance. Therefore, it is preferable that the compounding amount be as small as possible unless there is a purpose of improving the flame retardancy.
[0019]
In the molding material of the present invention, an organic substrate can be blended. Thereby, the viscosity at the time of melting can be adjusted and the moldability can be improved. The organic base material is not particularly limited, but is a crushed product of a cured thermosetting resin such as an epoxy resin or a phenol resin, or a crushed laminated board or decorative board in which a paper fiber base material is impregnated with a phenol resin or a melamine resin. And plant fibers such as wood powder, pulp, cloth pulverized powder, and paper pulverized powder, or pulverized products thereof, and crushed plant fruit husks such as coconut husk powder and fir powder.
The amount of the organic substrate is not particularly limited, but is preferably 20% by weight or less based on the entire molding material in consideration of dimensional stability. More preferably, it is 1 to 5% by weight. Thereby, an appropriate fluidity can be obtained at the time of heat melting.
[0020]
As described above, the molding material of the present invention is characterized by containing a novolak-type phenolic resin and hexamethylenetetramine, ferrous sulfate, and zeolite, and contains ferrous sulfate and zeolite. Due to the gas absorption effect, it is possible to suppress a decrease in the appearance of the surface of the molded body during the high-temperature solder dip treatment. In addition, corrosion of electrical contacts can be prevented by absorbing ammonia gas generated by decomposition of hexamethylenetetramine compounded as a curing agent.
[0021]
As a method for producing the molding material of the present invention, an ordinary method is employed. That is, a novolak-type phenol resin, hexamethylenetetramine, and ferrous sulfate, preferably blended with an organic base material having gas absorbency, and if necessary, other inorganic base materials, organic base materials, curing aids, After adding and mixing a pigment and a release agent, the mixture is melt-kneaded by a device such as a heating roll, cooled, and then pulverized or granulated to produce a product.
[0022]
Next, the trans bobbin of the present invention will be described.
The trans bobbin of the present invention is obtained by molding the above-mentioned molding material of the present invention. Here, the molding method is not particularly limited, but methods such as injection molding, transfer molding, and compression molding can be used. For example, when the injection molding method is used, molding can be performed under the following conditions.
(1) Mold temperature: 160 to 185 ° C
(2) Cylinder temperature: front 80-90 ° C, rear 40-50 ° C
(3) Injection pressure: effective pressure 1200 kg / cm ²
(4) Curing time: 20 to 70 seconds
【Example】
Hereinafter, the present invention will be described with reference to examples.
[0024]
1. Production of molding material A material having the composition shown in Table 1 was kneaded with a heating roll at 90 ° C. for 6 minutes. After cooling, it was pulverized to obtain a molding material. All the amounts shown in Table 1 represent% by weight.
[Table 1]

[0025]
2. Molding of Transbobbin The molding materials obtained in Examples and Comparative Examples were molded under the following conditions to obtain a transbobbin.
(1) Molding machine Toshiba IR-100
(2) Mold temperature 175 ° C
(3) Cylinder temperature 90 ° C at tip / 45 ° C after
(4) Injection pressure and speed Filling time set to 2 seconds (5) Curing time 20 seconds (6) Injection amount 20g / 1 shot (7) Number of shots 14 pieces / 1 shot (8) Shape of molded body 12 × 13mm coil bobbin with a height of 15mm
3. Evaluation The characteristics of the transbobin obtained by the above method were evaluated. Table 2 shows the results.
[Table 2]

[0027]
4. Evaluation Method (1) High Temperature Solder Characteristics The transformer bobbin was dipped in a solder bath at 500 ° C. for 5 seconds, and the occurrence of blisters, cracks, and warpage on the dip-treated surface was visually determined.
(2) Urethane coating insulation property retention (depending on generated gas)
The molding materials obtained in the examples and comparative examples were molded by the injection molding method according to the above (however, the number of shots was 3 shots / shot), and a 12.7 mm × 1 mm × 127 mm molded body (test Peace).
A container in which two urethane-coated electric wires were twisted and the three test pieces described above were put and sealed. After leaving it at 150 ° C. for 2 weeks, the dielectric strength between the two electric wires was measured by increasing the voltage in accordance with the “short time method” specified in JIS K 6911, and held against the dielectric strength before the treatment. The rate was calculated.
[0028]
Example 1 uses ferrous sulfate, zeolite, and calcined clay as the inorganic substrate, and wood flour as the organic substrate. Example 2 uses ferrous sulfate, zeolite, and calcined clay as the inorganic substrate. No organic substrate was used. As a result, the appearance after the solder immersion treatment at 500 ° C. was all good, and the insulation property retention of the urethane film was high. On the other hand, Comparative Examples 1 to 3 did not use one or both of ferrous sulfate and zeolite, and generated many cracks in the molded body after the solder immersion treatment. In addition, the insulation properties of the urethane coating were significantly reduced.
[0029]
【The invention's effect】
The present invention is a phenolic resin molding material using novolak type phenolic resin and hexamethylenetetramine, in which ferrous sulfate and zeolite are used to achieve a corrosive gas absorbing effect, particularly to capture ammonia gas. In addition, the transformer bobbin molded article obtained by using the molding material of the present invention has no abnormality such as blisters and cracks in appearance even when subjected to solder dip treatment at around 500 ° C. and causes corrosion of electrical contacts. There is no.

Claims (3)

A phenolic resin molding material comprising (a) a novolak type phenolic resin, hexamethylenetetramine, (b) ferrous sulfate, and (c) zeolite. For the entire molding material,
(A) a total of 30 to 60% by weight of a novolak-type phenol resin and hexamethylenetetramine;
(B) 2 to 15% by weight of ferrous sulfate;
(C) 10 to 30% by weight of zeolite
The phenolic resin molding material according to claim 1, comprising: A trans bobbin formed by molding the molding material according to claim 1.