JPH11325139A - Production of friction material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform degassing for preventing inconveniences such as cracks, reduced hardness or the like by setting initial pressurizing time to be longer in a thermomolding process. SOLUTION: A raw material blended with a fixed amount of friction agents is stirred and mixed so as to perform premolding, and thermomolding is executed based on the time of an illustrated pattern. Specifically, the time of heating at a low temperature having a small quantity of generated gas is extended, the time of pressure releasing for degassing is shortened, the time of pressurizing at a high temperature having an increased quantity of generated gas is shortened, and the time of pressure releasing is extended. A pressure is initially set high for improving heat conduction, the pressure is temporarily reduced for facilitating degassing when the quantity of generated gas is large and, thereafter, the pressure is gradually increased. In a thermomolding process using the producing method of friction agents, since degassing is performed according to the quantity of generated gas in the process, any defects such as cracks, a difference in failed hardness or the like for products are prevented, and good quality friction agents are produced.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は、自動車、鉄道車
両、産業機械等に使用されるブレーキ用摩擦材の製造方
法に関し、特にキレツの発生がなく、硬さの低下のない
ブレーキ用摩擦材の製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a friction material for a brake used in automobiles, railway vehicles, industrial machines, and the like. It relates to a manufacturing method.

【０００２】[0002]

【従来の技術】一般にブレーキ用摩擦材の製造は、摩擦
材原料の配合、攪拌、常温における予備成形、熱成形、
加熱（アフターキュア）、研磨等の仕上げ加工の各工程
を経て行われている。その中でも熱成形工程における成
形条件が製品の性能を直接左右するので、熱成形工程は
最も重要な工程である。通常、熱成形工程の初期段階で
は、加熱による摩擦材中のレジンの反応や揮発性物質の
気化に伴って発生するガスを排出するため、加圧・加圧
開放（「除荷」ともいう）を繰り返すガス抜き処理を複
数回行った後、所定の成形温度・圧力に数分間保持し、
熱成形体を得ている。その際に行われる従来のガス抜き
処理は、図４に示すように一定の時間間隔、一定の圧力
での加圧と加圧開放を繰り返す操作が行われるものであ
った。2. Description of the Related Art In general, friction materials for brakes are manufactured by mixing friction materials, stirring, preforming at room temperature, thermoforming, and the like.
It is performed through each step of finishing processing such as heating (after-curing) and polishing. Among these, the thermoforming step is the most important step because the molding conditions in the thermoforming step directly affect the performance of the product. Normally, in the initial stage of the thermoforming process, pressurization and pressurization (also referred to as "unloading") are performed in order to discharge the gas generated by the reaction of the resin in the friction material due to heating and the volatilization of volatile substances. After performing a plurality of degassing treatments repeatedly, hold at a predetermined molding temperature and pressure for several minutes,
A thermoformed body has been obtained. In the conventional degassing process performed at that time, as shown in FIG. 4, an operation of repeating pressurization at a constant time and a constant pressure and release of pressure are performed.

【０００３】[0003]

【発明が解決しようとする課題】しかしながら、熱成形
工程でのガスの発生量は、初期段階の初めの段階ではレ
ジンの熱硬化反応があまり進まないために少なく、時間
の経過で摩擦材の温度が上がってくると熱硬化反応が進
んで多くなるので、従来行われていたガス抜き処理は、
実際の発生ガス量の変化に十分対応していなかった。そ
のため、発生ガスの排出が十分でないことも多々あり、
それに起因して熱成形品にキレツが発生したり、硬さが
低い等の不具合が発生することがあり、発生ガスを十分
に排出できるガス抜き処理の手段或いは条件を確立する
ことが望まれていた。本発明は、上記した欠点を解消
し、キレツが発生したり、硬さが低い等の不具合が発生
しないガス抜き処理を行う摩擦材の製造方法を提供しよ
うとするものである。However, the amount of gas generated in the thermoforming process is small at the beginning of the initial stage because the thermosetting reaction of the resin does not proceed so much. When the temperature rises, the thermosetting reaction proceeds and increases, so the degassing process conventionally performed is
It did not sufficiently respond to the change in the actual amount of generated gas. Therefore, the emission of generated gas is often not enough,
As a result, cracks may occur in the thermoformed product or defects such as low hardness may occur, and it is desired to establish means or conditions for degassing treatment capable of sufficiently discharging generated gas. Was. An object of the present invention is to solve the above-mentioned drawbacks and to provide a method for producing a friction material that performs a degassing process that does not cause problems such as generation of cracks and low hardness.

【０００４】[0004]

【課題を解決するための手段】本発明は、下記の手段に
より上記の課題を解決した。 （１）繊維基材、結合材及び摩擦調整材を混合したもの
を所定の形状に予備成形した後、その予備成形体を熱成
形する熱成形工程を有し、その熱成形工程は、加圧とガ
ス抜きのための加圧開放とを繰り返し行うことからなる
摩擦材の製造方法において、該熱成形工程における初期
の加圧時間は、それに続く加圧時間より長くしたことを
特徴とする摩擦材の製造方法。 （２）前記初期加圧時間における加圧力は、初期加圧時
間に続く加圧時間における加圧力よりも大で、初期加圧
直後の加圧力を最も小さく、順次加圧力を大とすること
を特徴とする前記（１）記載の摩擦材の製造方法。The present invention has solved the above-mentioned problems by the following means. (1) After preforming a mixture of a fiber base material, a binder, and a friction modifier into a predetermined shape, the thermoforming step includes thermoforming the preformed body. And pressurizing and releasing for degassing, wherein the initial pressurizing time in the thermoforming step is longer than the subsequent pressurizing time. Manufacturing method. (2) The pressing force in the initial pressing time is larger than the pressing force in the pressing time following the initial pressing time, the pressing force immediately after the initial pressing is the smallest, and the pressing force is sequentially increased. The method for producing a friction material according to the above (1), which is characterized in that:

【０００５】[0005]

【発明の実施の形態】摩擦材の製造方法においては、従
来その熱成形工程で行われている加圧、加圧開放のサイ
クルとしては次のようなガス抜きが行われている。その
１例としては、ガス抜き条件は、図４に示すように、面
圧５５ＭＰａで１０秒加圧後、１０秒加圧開放の操作を
１サイクルとし、これを５回繰り返した後、面圧５５Ｍ
Ｐａ一定で３００秒加圧・保持して製品を得ている。前
記したように、このようなガス抜き条件がガス発生量の
変化に合致していないという問題に対応するために、実
際のガス発生量の変化がどのようなものかを知るために
予備実験を行った。 （予備実験）予め第１表に示す配合の摩擦材の原材料を
攪拌混合した混合物について加熱し、その昇温過程にお
ける温度と発生ガス量の関係を測定した。測定結果は、
図６に示すように低温時にはガス発生量は少なく、温度
が上昇するにつれてガス発生量は増え、１００℃付近で
ピークを示す。その後、１３０℃近辺まで低下した後、
再度上昇し１６０℃でピークを示した。DESCRIPTION OF THE PREFERRED EMBODIMENTS In a method of manufacturing a friction material, the following degassing is performed as a cycle of pressurization and release of pressure, which is conventionally performed in the thermoforming step. As an example, as shown in FIG. 4, the degassing conditions are as follows: the operation of pressing for 10 seconds at a surface pressure of 55 MPa and then releasing for 10 seconds is one cycle, and this is repeated five times. 55M
The product is obtained by pressing and holding at a constant Pa for 300 seconds. As described above, in order to cope with the problem that such a degassing condition does not match the change in the gas generation amount, a preliminary experiment was performed to know what the change in the actual gas generation amount was. went. (Preliminary experiment) A mixture prepared by stirring and mixing the raw materials of the friction material having the composition shown in Table 1 was heated in advance, and the relationship between the temperature and the amount of generated gas in the heating process was measured. The measurement result is
As shown in FIG. 6, the gas generation amount is small at low temperatures, increases as the temperature rises, and shows a peak near 100 ° C. Then, after the temperature drops to around 130 ° C,
It rose again and showed a peak at 160 ° C.

【０００６】[0006]

【表１】 [Table 1]

【０００７】図６にみるガス発生量の変化からすると、
熱成形の初期段階で温度が１００℃に達する前の期間で
はガス発生量が少ないため、加圧時間は長く、ガス抜き
のための加圧開放時間が短くてよく、温度が上昇して１
００℃付近、１６０℃付近や２１０℃付近ではガス発生
量が多いので、ガス抜きのための加圧開放時間が長い方
がよく、加圧時間は短くする方がよいことが判った。本
発明は、以上のような研究の結果を利用して熱成形を行
うものであるが、前記の加圧開放時間を長くするとか、
あるいは加圧時間は短くするとかいっても、加圧下で熱
成形を行うことが目的である以上、加圧開放時間を連続
して長くすると熱成形品の硬さが低下するなどの問題が
生じるから、その時間の設定を任意にすることは実際問
題としてできるとは限らないし、また好ましくない場合
もある。According to the change in the amount of generated gas shown in FIG.
In the initial stage of thermoforming, before the temperature reaches 100 ° C., the amount of gas generation is small, so that the pressurizing time is long, the pressurizing release time for degassing may be short, and the temperature rises to 1 ° C.
At around 00 ° C., around 160 ° C., and around 210 ° C., a large amount of gas was generated. Therefore, it was found that a longer pressurizing release time for degassing was better and a shorter pressurizing time was better. The present invention is to perform thermoforming using the results of the above research, but to increase the pressure release time,
Or, even if the pressurizing time is shortened, the purpose is to perform thermoforming under pressurization, but if the pressurizing and releasing time is continuously increased, problems such as a decrease in the hardness of the thermoformed product occur. Therefore, it is not always possible to make the setting of the time arbitrarily as a practical problem, and sometimes it is not preferable.

【０００８】そのため、加圧開放時間を長くするといっ
ても１回に取れる加圧開放時間の時間の長さに限度があ
るので通算で行うようにすることができる。その１例と
しては、後述する実施例１で説明する図１に示すよう
に、圧力開放期間を前の方より後の方で長くするように
することができる。また、装置の機器の運転上、１回の
加圧開放時間を同じ時間にした方が好ましい場合には、
加圧時間の方を段々短くするようにしても、同様の目的
を達成することができる。これは実施例２で説明する図
２に示している。本発明は、そのガス抜きの加圧開放時
間の設定には種々のやり方を取れることは容易に理解で
きるところである。[0008] For this reason, even if the pressurizing and releasing time is lengthened, there is a limit to the length of the pressurizing and releasing time that can be taken at one time. As one example, as shown in FIG. 1 described in a first embodiment to be described later, the pressure release period can be made longer in the rear than in the front. In addition, in the case where it is preferable to set one pressurizing and releasing time to the same time in the operation of the equipment of the apparatus,
The same object can be achieved even if the pressurizing time is gradually shortened. This is shown in FIG. 2 described in the second embodiment. It can be easily understood that the present invention can take various methods for setting the pressure release time for degassing.

【０００９】本発明の摩擦材の製造方法は、従来知られ
ている摩擦材の製造工程において行うことができる。従
来知られている摩擦材の製造方法の１例としてディスク
ブレーキ用ディスクパットの製造工程を挙げると次のよ
うな工程からなる。すなわち、ディスクブレーキ用ディ
スクパットの製造工程においては、板金プレスにより所
定の形状に成形され、脱脂処理及びプライマー処理が施
され、そして接着剤が塗布された裏金と、耐熱性有機繊
維や無機繊維、金属繊維等の繊維材料と、無機・有機充
填材、摩擦調整材及び熱硬化性樹脂バインダ等の粉末原
料とを配合し、攪拌により十分に均質化した原材料を常
温にて所定の圧力で成形（予備成形）して作製した予備
成形体とを、熱成形工程において所定の温度及び圧力で
熱成形して両部材を一体に固着し、アフタキュアを行
い、最終的に仕上げ処理を施す工程からなる。The method for producing a friction material of the present invention can be performed in a conventionally known friction material production process. As an example of a conventionally known method of manufacturing a friction material, a manufacturing process of a disc pad for a disc brake is described as follows. That is, in the manufacturing process of the disc pad for disc brakes, the back metal is formed into a predetermined shape by a sheet metal press, subjected to a degreasing process and a primer process, and is coated with an adhesive, a heat-resistant organic fiber or an inorganic fiber, A fiber material such as a metal fiber and a powder material such as an inorganic / organic filler, a friction modifier and a thermosetting resin binder are blended, and the raw material sufficiently homogenized by stirring is formed at room temperature under a predetermined pressure ( And a preforming body produced by preforming), in a thermoforming step, thermoforming at a predetermined temperature and pressure to fix both members together, perform after-curing, and finally perform a finishing treatment.

【００１０】前記した有機繊維としては、芳香族ポリア
ミド繊維（例えばアラミド繊維）、アクリル繊維が挙げ
られ、無機繊維としては例えばチタン酸カリウム繊維や
アルミナ繊維等のセラミック繊維、ガラス繊維、カーボ
ン繊維、ロックウール等が挙げられ、また金属繊維とし
ては例えば銅繊維やスチール繊維が挙げられる。無機充
填材としては、例えばバームキュライトやマイカ等の鱗
片状無機物、硫酸バリウムや炭酸カルシウム等の粒子が
挙げられ、有機充填材としては、例えば合成ゴムやカシ
ュー樹脂等が挙げられる。熱硬化性樹脂バインダとして
は、例えばフェノール樹脂（ストレートフェノール樹
脂、ゴム等による各種変性フェノール樹脂を含む）、メ
ラミン樹脂、ポリイミド樹脂、ＢＴ樹脂等を挙げること
ができる。また、摩擦調整材としては、例えばアルミナ
やシリカ、マグネシア、ジルコニア、酸化クロム、石英
等の金属酸化物等を、固体潤滑剤としては、例えばグラ
ファイトや二硫化モリブデン等を挙げることができる。Examples of the organic fibers include aromatic polyamide fibers (eg, aramid fibers) and acrylic fibers. Examples of inorganic fibers include ceramic fibers such as potassium titanate fiber and alumina fiber, glass fibers, carbon fibers, and rock fibers. Wool and the like can be mentioned, and examples of the metal fiber include a copper fiber and a steel fiber. Examples of the inorganic filler include scaly inorganic substances such as balm curite and mica, and particles such as barium sulfate and calcium carbonate. Examples of the organic filler include synthetic rubber and cashew resin. Examples of the thermosetting resin binder include a phenol resin (including various modified phenol resins such as straight phenol resin and rubber), a melamine resin, a polyimide resin, and a BT resin. Examples of the friction modifier include metal oxides such as alumina and silica, magnesia, zirconia, chromium oxide, and quartz. Examples of the solid lubricant include graphite and molybdenum disulfide.

【００１１】従来行われている熱成形工程を図面を用い
て説明すると、図５に示すような上型２、中型３、下型
４とからなる熱成形金型５を、ヒータ８をそれぞれ有す
る上部の加熱板６と下部の加熱板７の間に設けた熱成形
装置１を用いる。その上型２と下型４との間に摩擦材１
３と裏金１４からなる予備成形体１２をに投入し、ヒー
タ８に通電して、加熱板６と加熱板７により予備成形体
１２を加熱するようにする。加熱板６と加熱板７の上下
から加圧して、同時に加熱加圧が行われるようにして熱
成形を行うものである。この熱成形装置１を用いても本
発明を実施することができる。本発明は、そのガス抜き
の操作が重要であるため、図３に示す熱成形装置１を用
いると、一層容易に行うことができる。図３に示す熱成
形装置１は、上型２の側部に凹部９を設け、また中型３
の側面部にガス抜き孔１０が開いている熱成形金型５を
用いる。ガス抜き孔１０の先にガス流量計１１を設置し
ておき、ガス流量を記録するようにできる。この装置に
よれば、ガス抜きを迅速に行うことができる。A conventional thermoforming process will be described with reference to the drawings. A thermoforming mold 5 including an upper mold 2, a middle mold 3 and a lower mold 4 as shown in FIG. The thermoforming device 1 provided between the upper heating plate 6 and the lower heating plate 7 is used. Friction material 1 between upper mold 2 and lower mold 4
The preformed body 12 composed of the backing metal 3 and the backing metal 14 is put into the heater 8, the heater 8 is energized, and the preformed body 12 is heated by the heating plate 6 and the heating plate 7. Thermoforming is performed by applying pressure from above and below the heating plate 6 and the heating plate 7 so that heating and pressing are performed simultaneously. The present invention can also be implemented using this thermoforming device 1. In the present invention, since the degassing operation is important, it can be more easily performed by using the thermoforming apparatus 1 shown in FIG. The thermoforming apparatus 1 shown in FIG.
A thermoforming mold 5 having a gas vent hole 10 in the side surface of is used. A gas flow meter 11 can be installed at the tip of the gas vent hole 10 to record the gas flow rate. According to this device, degassing can be performed quickly.

【００１２】[0012]

【実施例】以下、実施例により本発明を具体的に説明す
るが、本発明はこれらのみに限定されるものではない。EXAMPLES The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples.

【００１３】実施例１ （本発明法）第１表に示した配合と同じ配合の摩擦材の
原材料を攪拌混合し、予備成形し、圧力、時間を図１に
示すパターンに設定して熱成形を行った。このパターン
設定の基本的な考えは、ガス発生量の少ない低温時の加
圧時間を長くし、ガス抜きの加圧開放時間を短くし、ガ
ス発生量が多くなる高温時の加圧時間を短くし、加圧開
放時間を長くした。また圧力は、最初は材料間の熱伝導
を良くするために高くし、ガス発生量が多くなる頃は、
一旦圧力を下げてガスが抜け易くし、その後徐々に高く
していった。 （従来法）ガス抜き条件は、図４に示すように、面圧５
５ＭＰａで１０秒加圧後、１０秒加圧開放の操作を１サ
イクルとし、これを５回繰り返した後、面圧５５ＭＰａ
一定で３００秒加圧・保持して製品を得た。Example 1 (Method of the Invention) Raw materials of a friction material having the same composition as shown in Table 1 were mixed with stirring, preformed, and thermoformed by setting the pressure and time to the pattern shown in FIG. Was done. The basic idea of this pattern setting is to lengthen the pressurization time at low temperature where gas generation is small, shorten the pressure release time for gas release, and shorten the pressurization time at high temperature where gas generation is large. And the pressure release time was lengthened. In addition, the pressure is initially increased to improve the heat transfer between the materials, and when the amount of gas generation increases,
Once the pressure was lowered, the gas escaped easily, and then gradually increased. (Conventional method) As shown in FIG.
After pressurizing for 10 seconds at 5 MPa, the operation of pressing and releasing for 10 seconds was defined as one cycle, and this was repeated 5 times.
The product was pressed and held at a constant pressure for 300 seconds to obtain a product.

【００１４】（測定結果）両方の熱成形工程で得た製品
について、その性質を測定したところ、第２表に示すよ
うに本発明法による本発明法品は、従来法による従来の
製品に比して、キレツの発生率は低く、硬さも高いこと
が確認された。なお、第２表の本発明品、従来品ともに
キレツの発生や硬さ不良の差が出やすいように、原材料
をわざと十分に吸湿させてから、熱成形を行ったもので
ある。(Measurement results) The properties of the products obtained in both the thermoforming steps were measured. As shown in Table 2, the products of the present invention according to the present invention were compared with those of the conventional products according to the conventional method. As a result, it was confirmed that the rate of occurrence of cracks was low and the hardness was high. In addition, both the product of the present invention and the conventional product shown in Table 2 were obtained by intentionally sufficiently absorbing the raw materials so as to easily cause a difference in generation of cracks and poor hardness, and then subjected to thermoforming.

【００１５】[0015]

【表２】 [Table 2]

【００１６】実施例２ （予備成形体の作製）実施例１と同じ配合の原材料を混
合、攪拌した後、常温で加圧成形を行い、パッドの予備
成形体を作製した。 （熱成形工程） （１）本発明法 この予備成形体１２を、図３に示す熱成形装置１の熱成
形金型５に投入し、図２のガス抜きパターンに示すよう
に、加圧時間と加圧開放時間の切替えを流量計の測定に
よる発生ガス量の変化に応じて行い、発生ガス量が少な
い時は加圧時間を長くし、多い時は加圧時間を短くし、
ガス抜きの加圧開放時間は全体を通じてほぼ一定とし
た。これにより、ガス抜きのための加圧開放操作を行う
時間間隔は最初は長く、後半は短くなっている。なお、
当然のことながら、このパターンは製品のサイズ、配合
成分、温度上昇速度等によって、ガスの発生量と時間の
関係が変わるのに応じて適宜変更する必要がある。Example 2 (Preparation of Preform) After mixing and stirring the raw materials having the same composition as in Example 1, pressure molding was performed at room temperature to prepare a pad preform. (Thermoforming Step) (1) Method of the Present Invention The preformed body 12 is put into the thermoforming mold 5 of the thermoforming apparatus 1 shown in FIG. And switching of the pressurization release time according to the change in the amount of gas generated by the flow meter measurement.If the amount of generated gas is small, increase the pressurization time, if it is large, decrease the pressurization time,
The pressure release time for degassing was almost constant throughout. As a result, the time interval for performing the pressure release operation for degassing is initially long and short in the latter half. In addition,
As a matter of course, this pattern needs to be appropriately changed according to the size of the product, the composition, the temperature rise rate, and the like, and the relationship between the gas generation amount and the time changes.

【００１７】（２）従来法 次に前項と同様な熱成形を、従来法に沿って、図４に示
すようにガス抜き条件である加圧１０秒後、加圧開放１
０秒を１サイクルとし、これを５回繰り返した後、５５
ＭＰａ一定で３００秒間加圧、保持して製品を得た。こ
のガス抜き時のガス量をガス流量計で測定、記録したと
ころ、ガス抜き初期には発生ガスはあまり多くなく、予
備成形体１２の温度が上昇してくるとガス発生量が急激
に増加していることが判った。 （測定結果）両方法の製品を比較したところ、本発明法
による製品は、第２表に示すところと同様な結果が得ら
れた。キレツの発生率は低く、硬さも高いことが確認で
きた。なお、ここで熱成形したものは、本発明品、従来
品ともにキレツの発生や硬さ不良の差が出やすいよう
に、原材料をわざと十分に吸湿させてから、熱成形を行
ったものである。(2) Conventional method Next, the same thermoforming as that described in the preceding paragraph was carried out according to the conventional method.
Zero cycle is defined as one cycle, and after repeating this five times, 55
The product was obtained by pressing and holding at a constant MPa for 300 seconds. When the amount of gas at the time of degassing was measured and recorded with a gas flow meter, the amount of gas generated was not so large at the beginning of degassing, and the gas generation amount increased sharply as the temperature of the preform 12 increased. It turned out that. (Measurement results) When the products of both methods were compared, the products according to the method of the present invention obtained the same results as shown in Table 2. It was confirmed that the incidence of cracks was low and the hardness was high. Here, the thermoformed product is a product obtained by intentionally absorbing the raw materials sufficiently so that the difference in the occurrence of cracks and poor hardness easily appears in both the present invention product and the conventional product, and then thermoformed. .

【００１８】[0018]

【発明の効果】本発明によれば、摩擦材の製造方法にお
ける熱成形工程で、その過程でのガス発生量に即したガ
ス抜きを行うことができるので、製品にキレツの発生や
硬さ不良の差が出るという欠点が生じることがなく、品
質の良い摩擦材を製造することができる。また、摩擦材
の製造での生産性を上げることができる。本発明で用い
る熱成形装置では、熱成形工程の過程でのガス発生量を
知ることができ、それに即応するガス抜き操作を行うこ
とができる。According to the present invention, in the thermoforming step in the method of manufacturing a friction material, gas can be vented in accordance with the amount of gas generated in the process, so that the product has cracks or has poor hardness. Therefore, it is possible to produce a high-quality friction material without causing a drawback that a difference is generated. Further, productivity in the production of the friction material can be increased. With the thermoforming apparatus used in the present invention, the amount of gas generated during the thermoforming process can be known, and a gas releasing operation can be performed in response to the amount.

【図面の簡単な説明】[Brief description of the drawings]

【図１】本発明の実施例１におけるガス抜き条件を表わ
すダイアグラムを示す。FIG. 1 is a diagram showing degassing conditions in Embodiment 1 of the present invention.

【図２】本発明の実施例２におけるガス抜き条件を表わ
すダイアグラムを示す。FIG. 2 is a diagram showing degassing conditions in Embodiment 2 of the present invention.

【図３】本発明を行うのに使用するのに適した熱成形装
置の縦断面図を示す。FIG. 3 shows a longitudinal section of a thermoforming device suitable for use in carrying out the present invention.

【図４】従来の熱成形法におけるガス抜き条件を表わす
ダイアグラムを示す。FIG. 4 is a diagram showing degassing conditions in a conventional thermoforming method.

【図５】従来の熱成形法において使用されている熱成形
装置の縦断面図を示す。FIG. 5 is a longitudinal sectional view of a thermoforming apparatus used in a conventional thermoforming method.

【図６】１例の摩擦材原材料の混合物を加熱した際の時
間とガス発生量との関係を表わすグラフを示す。FIG. 6 is a graph showing a relationship between time and gas generation amount when a mixture of friction material raw materials of one example is heated.

【符号の説明】[Explanation of symbols]

１ 熱成形装置 ２ 上型 ３ 中型 ４ 下型 ５ 金型 ６ 加熱板 ７ 加熱板 ８ ヒータ ９ 凹部 １０ ガス抜き孔 １１ ガス流量計 １２ 予備成形体 １３ 摩擦材 １４ 裏金 DESCRIPTION OF SYMBOLS 1 Thermoforming apparatus 2 Upper die 3 Middle die 4 Lower die 5 Die 6 Heating plate 7 Heating plate 8 Heater 9 Concave part 10 Gas vent hole 11 Gas flow meter 12 Preformed body 13 Friction material 14 Back metal

Claims (2)

【特許請求の範囲】[Claims] 【請求項１】 繊維基材、結合材及び摩擦調整材を混合
したものを所定の形状に予備成形した後、その予備成形
体を熱成形する熱成形工程を有し、その熱成形工程は、
加圧とガス抜きのための加圧開放とを繰り返し行うこと
からなる摩擦材の製造方法において、該熱成形工程にお
ける初期の加圧時間は、それに続く加圧時間より長くし
たことを特徴とする摩擦材の製造方法。1. A thermoforming step of preforming a mixture of a fibrous base material, a binder, and a friction modifier in a predetermined shape, and then thermoforming the preformed body.
A method for producing a friction material, comprising repeatedly performing pressurization and pressurization and release for degassing, wherein the initial pressurization time in the thermoforming step is longer than the subsequent pressurization time. Manufacturing method of friction material. 【請求項２】 前記初期加圧時間における加圧力は、初
期加圧時間に続く加圧時間における加圧力よりも大で、
初期加圧直後の加圧力を最も小さく、順次加圧力を大と
することを特徴とする請求項１記載の摩擦材の製造方
法。2. The pressurizing force in the initial pressurizing time is larger than the pressurizing force in the pressurizing time following the initial pressurizing time,
2. The method for manufacturing a friction material according to claim 1, wherein the pressing force immediately after the initial pressing is minimized and the pressing force is sequentially increased.