JPH0239647B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the production of molded products such as brake pads and brake shoes that are parts of disc brakes, drum brakes, etc. used in vehicles such as automobiles and motorcycles, and industrial equipment such as agricultural equipment. It is something.

Brake parts such as brake parts and brake shoes are made of metals such as processed steel products, iron castings, aluminum die castings, etc., which are used as backing plates or supports for the friction material and are bonded to the friction material using adhesives or rivets. things are widely used. However, manufacturing brake parts that combine these metals and friction materials requires complicated processes such as molding and processing the friction materials, processing the metals, and adhering them. In order to prevent poor bonding, it is necessary to carefully control the properties of the binder and the bonding method, which requires a high degree of skill and technology. or,
This method has the disadvantage that the weight of the brake parts obtained by using metal is large, and this method is not preferred from the viewpoint of energy saving.

Therefore, as a method to improve this drawback, a laminated glass wool woven fabric or asbestos woven fabric impregnated with phenolic resin is preformed into an angle shape, placed in a mold, and the surface of the woven glass wool fabric or asbestos fabric is coated with phenolic resin powder. A method of simultaneously molding a brake shoe assembly by sprinkling a preformed friction material made of short asbestos fibers, cashew powder, phenolic resin, etc. on top of the preformed friction material, and heating and pressurizing it in a mold.
-18012) has been reported. However, this method requires complicated steps such as preparing the back plate material, preforming the friction material, and dispersing the binder. Moreover, the molding conditions are 1600°C and require about 3 hours, which is not practical. Furthermore, when performing preforming and shaping, woven fabric is used, which has the disadvantage of poor flow, poor formability unless cut to fit the shape in advance, and large variations in strength.

In addition, as a manufacturing method for brake pads, a backing plate is formed by heating and pressurizing a mixture consisting of a thermosetting resin, an anti-friction agent, and glass fiber in a mold with an uneven surface on one side, and one side of this backing plate. A method for manufacturing a disc brake pad (Japanese Patent Publication No. 53-30868) has been reported, which comprises a friction material fixed to the pad so as to fit into the concave and convex portions. In this method, the weight is reduced because the back plate is made of plastic, but the back plate is pre-formed in the mold and then re-set together with the friction material in a separate mold to integrate it. The process is complicated, two types of molds are required, and the adhesiveness is poor unless the back plate is provided with concavities and convexities.

Furthermore, as another method for manufacturing disc brake pads, both preforms, the back plate of which is made of compressed granular material, and the friction material layer of which is made of compressed granular material, are placed in a mold, and heat and pressure are simultaneously applied to form the preform. There is a method (Japanese Unexamined Patent Publication No. 126133/1983) of combining and integrating the two. but,
In such a method, each preform contains the same resin binder, but when compressed granular material is used as the backing layer, the length of the reinforcing material contained in the granular material is limited and only short fibers can be used. It has the disadvantage that the strength necessary for a brake cannot be obtained because it is bent, and it cannot be set in a mold unless both are preformed. Furthermore, since the same binder is used for the back plate layer and the friction material layer, completely different performance requirements for each brake component are not necessarily satisfied.

As mentioned above, conventional methods have been reported in which metal is replaced with plastic and molded integrally or simultaneously, but these methods are complicated and have some drawbacks in terms of adhesion with moldable friction materials, strength, etc., and none of them are practical. It wasn't the point.

Therefore, the inventors of the present invention omitted the preforming process for the back plate or support, simplified the process by reducing the number of molds used, and created a brake with excellent adhesion between the friction material and the back plate, and a lightweight and strong brake. As a result of intensive studies to obtain a molded product for use in friction materials, the sheet-shaped molding material (1) consisting of a resol-type phenolic resin, a viscous agent, a filler, and a reinforcing material was made into a friction material before or after curing without preforming. In combination with (2), the process is significantly simplified (reduced process time to about 1/4) by filling the mold into a heated mold, heating, and pressurizing the material. The present inventors have now completed the present invention by discovering that a molded product with excellent adhesive properties can be obtained, and furthermore, by using a phenolic resin, a molded product with significantly improved heat resistance can be obtained.

That is, the present invention is capable of forming a friction material (2) before or after curing without preforming an uncured sheet-like molding material (1) consisting of a resol type phenolic resin, a thickener, a filler, and a reinforcing material. Provided is a method for producing a molded product for brakes, which is characterized in that the combination is filled into a heated mold, heated and press-molded.

Sheet-shaped molding material used in the present invention (1)
is a non-stick material that is sandwiched between two films and has exactly the same form as sheet molding material (SMC) that generally uses unsaturated polyester. It consists of reinforcing material.

The resol type phenolic resin used in the present invention is generally prepared by combining one or more phenols such as phenol, resorcinol, xylenol, hydroquinone, bisphenol A, butylphenol, and octylphenol, and an aldehyde such as formaldehyde in the presence of an alkaline catalyst. It is reacted under the manufacturing conditions of
Or it is a liquid resin containing alcohol.
Although the raw material composition of such resol-type phenolic resins has a relatively wide range, it is usually expressed as an aldehyde/phenol molar ratio (hereinafter referred to as "F/phenol").
It is abbreviated as "P". ) from 0.8 to 3.0, preferably from 1.0 to
It is within the range of 2.5. The pH of the above phenolic resin is suitably within the range of 3 to 12 as long as the stability of the resin itself is not affected, and within this range molding operations become easier.

Thickeners used in combination with resol type phenolic resins are extremely important formulation components. In other words, the type of thickener and the amount added determine the basic properties of the resulting molding material, such as thickening properties, stickiness, film releasability, and flowability during molding. Furthermore, since it also serves as a curing agent, it is possible to significantly shorten the molding time. Therefore, alkaline earth metal oxides or hydroxides are more effective as thickeners in the present invention, and are particularly effective in rapidly thickening, short maturing time, without stickiness, and in releasing the film. Mg and
Compounds selected from Ca oxides or hydroxides are preferred. The amount of thickener used is usually 0.5 to 1.5 parts by weight, preferably 1 to 1.5 parts by weight per 100 parts by weight of resin.
It is 10 parts by weight.

Typical fillers used in the present invention include aluminum hydroxide, calcium carbonate, calcium sulfate, barium sulfate, clay, and talc. Among them, aluminum hydroxide improves the flame retardancy of molded products. This is preferable because it can also improve The amount of such filler added varies somewhat depending on the viscosity of the resin, but is usually 30 to 200 parts by weight per 100 parts by weight of the resin, and if it is used in a large amount exceeding 200 parts by weight, fiber reinforcement will occur. Impregnation into the base material becomes poor.

Further, if necessary, an internal mold release agent may be added to the sheet-like molding material, and for example, metal soaps, phosphates, long chain fatty acids or salts thereof can be used. The appropriate amount of the mold release agent used is 1 to 10 parts by weight per 100 parts by weight of the resin.

Furthermore, the reinforcing materials used in the present invention include chopped strand mat, glass chip, continuous mat, glass fiber or carbon fiber such as roving or cloth, inorganic fiber such as boron fiber, asbestos, whisker, vinylon, polyamide, etc. Examples include organic fibers. The content of the reinforcing material in the sheet-like molding material is usually 10 to 70% by weight, preferably 20% by weight.
~70% by weight.

The production of sheet-like molding materials using the various raw materials described above can be carried out using an SMC production machine that is generally applied to unsaturated polyester resins. Next, the sheet-shaped molding material obtained using this SMC manufacturing machine is usually left at room temperature or heated to 30 to 60°C to age.

The thus obtained aged sheet molding material is cut into appropriate dimensions during molding, the film used during molding is peeled off and set in a mold together with the friction material, and then pressurized and heated to form a molded product. However, the pressure at this time is preferably 20 to 180 Kg/ ^cm2 ,
Further, the mold temperature is preferably 100 to 180°C.

Compared to the conventional method of impregnating glass cloth with phenolic resin and then using prepreg to remove the solvent, the present invention uses a sheet-shaped molding material that has good fluidity when pressurized, so it can be molded in the same shape as the molded product. There is no need to cut the material, and there is no need for preforming. That is, it is sufficient to cut it into appropriate dimensions and set it in a mold with a specified weight. still,
The above-mentioned thickener, i.e. Mg, Ca hydroxide or oxide, acts as a hardening agent, so it hardens quickly and can be molded in about 5 minutes (150℃), and there is no need to vent gas during the process. .

Further, in comparison with conventional granular materials, the sheet-form molding material of the present invention can provide sufficient mechanical strength to be used for brakes because long fibers of completely different types of reinforcing materials can be used. In addition, compared to granular materials, it is easier to set regardless of whether the mold is turned off or the female mold is positioned.

Furthermore, conventional sheet molding materials using unsaturated polyester resins have a drawback in heat resistance (hot strength) for brake applications, but sheet molding materials using the phenolic resin of the present invention have significantly improved heat resistance. It is practical for brake applications.
Further, since phenolic resin or asbestos is usually used as the friction material, sufficient adhesive strength with the friction material can be obtained through chemical bonding.

The friction material used in the present invention may be a general friction material used for brakes, such as resol or novolak type phenolic resin as a binder, various fibers such as asbestos and glass fiber as a base material, and a friction modifier. , fillers, etc.

In the present invention, molding of a brake molded product using a sheet-like molding material and a friction material can be carried out by the following two methods. (i) A raw friction material before curing is combined with a sheet-like molding material (for back plate or support), which is preferably appropriately cut and overlapped, and set in a mold, heated, pressurized, and simultaneously molded. Do the following. In this case, the molding conditions are 120~200℃, preferably 130~
5 to 10 minutes at 180°C is appropriate. (ii) A semi-cured or fully cured friction material is combined with a sheet-like molding material (for back plate or support), which is preferably appropriately cut and overlapped, and set in a mold, heated and pressurized to integrate. Perform molding. The molding conditions are the same as in case (i).

The brake molded product thus obtained has excellent adhesive properties in which the friction material and the backing plate or support are integrated, and has excellent mechanical strength and heat resistance, and has no practical problems, and is superior to conventional products. This makes it possible to significantly simplify the molding process and reduce weight compared to the conventional method. Therefore, such a molded product is useful for brakes for motorcycles, automobiles, agricultural machinery, rotating machinery, and the like.

Hereinafter, the present invention will be specifically explained with reference to Examples, and all parts and percentages are based on weight unless otherwise specified.

Reference example 1 (Manufacture of sheet-shaped molding material) Resol type liquid phenolic resin: Daislick
301 (manufactured by Dainippon Ink & Chemicals Co., Ltd.) 29% Thickener and hardener: MgO 2 Filler: Aluminum hydroxide 29 Reinforcement material: 25mm chopped strand glass 40 Regular SMC with the above composition Using a manufacturing machine, the material was formed into a sheet by a conventional method, and then aged to produce a non-sticky and fluid sheet-like molding material (SMC-1). The molding material was roughly cut into strips to fit into the mold.

Reference Example 2 (Production of sheet-shaped molding material) In Reference Example 1, a sheet-shaped molding material (SMC-2) was produced by replacing the reinforcing material with glass roving cloth (570 g/m ² ) and the filler with calcium carbonate. did.

Reference Example 3 (Manufacture of friction material) Resol-type liquid phenolic resin: Plyoven TD-799 (manufactured by Dainippon Ink and Chemicals Co., Ltd.) 15% Reinforcement material: Asbestos 56〃 Friction modifier: Cashew dust 17〃 Filler: Barium sulfate 12〃 A friction material (friction material 1) prepared by cold extruding a mixture of the above ingredients into a flat plate using an extruder (friction material 1) was cut into strips.

Reference Example 4 (Friction Material) A friction material (Friction Material 2) was prepared by replacing the resin of Reference Example 3 with a novolac-type powdered phenolic resin Pryopen 5510 (manufactured by Dainippon Ink & Chemicals Co., Ltd.).

Example 1 10 g of strip-shaped friction material-1 (Reference Example 3) and 48 g of sheet-shaped molding material SMC-1 (Reference Example 1) were stacked together and placed appropriately into a mold for a motorcycle brake shoe assembly. , and then molded at 150°C for 5 minutes. The molded product obtained was an excellent co-molded product in which the friction material of the lining portion and the sheet-like molding material of the support portion were completely filled to every corner of the mold, and there was no fill or void. The weight of the molded product obtained is 57
It was hot at g. Its compressive strength is 1020Kg at room temperature, 200
The weight was 840 kg when heated at ℃, which was sufficient strength for practical use. The adhesive strength between the lining part and the support part was strong enough that there was no peeling of both parts, and there was no problem in use, although the lining part broke in peel tests at room temperature and hot at 200℃. It was hot. The total process time is 1 minute for cutting the friction material, 2 minutes for cutting the sheet molding material, and 8 minutes for setting and pressing.
It took 11 minutes for a human worker.

Example 2 10 g of strip-shaped friction material-1 and 51 g of sheet-shaped molding material SMC-2 (Reference Example 2) were stacked together, placed appropriately into a mold for a motorcycle brake shoe assembly, and then heated at 150°C. It was molded for 5 minutes. The molded product obtained was an excellent co-molded product in which the friction material of the lining portion and the sheet-like molding material of the support portion were completely filled to every corner of the mold, and there was no fill or void. The weight of the molded product obtained was 60 g. Its compressive strength is 1100Kg at room temperature and 200℃ hot.
Weighing 900 kg, it was strong enough for practical use. The adhesive strength between the lining part and the support part was the same as in Example 1. Incidentally, the process time was also 11 minutes as in Example 1.

Example 3 10 g of strip-shaped friction material-2 (Reference example 2) and 251 g of sheet-shaped molding material SMC-2 were stacked together and put into a mold for a motorcycle brake shoe assembly.
Thereafter, it was molded at 150°C for 5 minutes. The obtained molded product was an excellent co-molded product similar to Examples 1 and 2. The weight of the molded article was 60 g. In addition, its compressive strength was 1150Kg, and 920Kg at 200°C, which was sufficient for practical use. The adhesive strength between the lining part and the support part was the same as in Example 1. Incidentally, the process time was also 11 minutes as in Example 1.

Example 4 10 g of a strip of friction material-1 was placed in a lining mold and molded at 150° C. for 5 minutes to obtain a cured bow-shaped friction material molded product (lining). Obtained lining and sheet molding material (SMC-2)
The mixture was stacked with 51g and put into a mold for a motorcycle assembly, and molded at 150°C for 5 minutes. The obtained molded product had a lining part and a support part molded from a sheet-like molding material completely integrated.
The weight of the molded article was 60 g. Compressive strength at room temperature
The strength was 1130Kg, and 910Kg at 200℃ when hot, which was sufficient for practical use. The adhesive strength between the lining part and the support part was the same as in Example 1. The construction time is 1 minute for cutting the friction material and 6 minutes for setting and forming the lining.
The cutting time for the sheet-shaped molding material was 2 minutes, and the time for setting and pressing the lining and sheet-shaped molding material in combination was 8 minutes, making the total time for one worker 17 minutes.

Example 5 10 g of strip-shaped friction material-2 was set in a lining mold and molded at 150° C. for 5 minutes to obtain a cured arc-shaped friction material molded product (lining). Obtained lining and sheet molding material SMC-251g
These were placed on top of each other, placed in a mold for a motorcycle assembly, and molded at 150°C for 5 minutes. The obtained molded product had a lining part and a support part molded from a sheet-like molding material completely integrated.
The weight of the molded article was 60 g. Its compressive strength was 1170 Kg at room temperature and 940 Kg at 200°C, which was sufficient for practical use. The adhesive strength between the lining part and the support part was the same as in Example 1. Incidentally, the process time was 17 minutes as in Example 4.

Comparative Example 1 10 g of strip-shaped friction material-1 was placed in a lining mold and molded at 150° C. for 5 minutes to obtain a cured arc-shaped friction material molded product (lining). Next, a separately produced 58g aluminum die-cast support and an upper lining were heated in a heating device for 30 minutes using epoxy-modified phenol to obtain a motorcycle brake molded product in which the lining and support were integrated. . The weight of the molded product obtained was 69 g.
Its compressive strength is 1200Kg at room temperature and 1200Kg at 200℃ hot.
Kg, and is the same as the brake molding for motorcycles that is in practical use. The process time for the molded product using this aluminum die-cast support was 45 minutes per worker, including the bonding process.

Claims (1)

[Claims] 1 Uncured sheet-shaped molding material consisting of resol type phenolic resin, thickener, filler and reinforcing material (1)
Friction materials before or after curing without preforming
A method for producing a molded product for brakes, which is characterized by filling a mold in combination with (2), heating, and pressurizing the molded product.