JP6497088B2 - Manufacturing method of back plate, back plate and brake pad - Google Patents

Description

  The present invention relates to a method for manufacturing a back plate, a back plate, and a brake pad.

  A brake pad for a disc brake generally includes a lining (friction material) for braking the disc and a back plate (back plate) that supports the lining. The back plate is required to have heat resistance, brake resistance, and high mechanical strength in a high temperature atmosphere in order to support the lining. Therefore, conventionally, a ceramic plate or a metal plate has been used as the back plate. However, the ceramic plate and the metal plate have problems in that they are heavy, take a long time to process, and have a high cost.

  Therefore, recently, for the purpose of weight reduction and cost reduction, as a substitute for a ceramic plate or a metal plate, a plate formed using a synthetic resin mixed with fibers is used for the back plate. It is being considered.

  Such a back plate is generally formed by performing compression molding, injection molding, or the like using pellets obtained by solidifying a fiber group with a resin (see, for example, Patent Document 1).

  However, in the back plate obtained by the conventional manufacturing method, there are dense portions and coarse portions in the back plate, and the fibers are not sufficiently uniformly dispersed. Therefore, the back plate obtained by the conventional manufacturing method has a problem that sufficient mechanical strength cannot be obtained and the strength varies among products.

JP 2012-96370 A

  The present invention provides a back plate manufacturing method capable of easily manufacturing a back plate excellent in mechanical strength, provides a back plate excellent in mechanical strength, and a highly reliable brake pad. Is to provide.

Such an object is achieved by the present invention described in the following (1) to ( 7 ).
(1) A manufacturing method of a back plate joined to the friction material of a brake pad including a friction material,
Preparing a pellet raw material containing resin and fibrils;
Cutting the pellet raw material to obtain a plurality of pellets containing the resin and fibers obtained by cutting the fibrils;
Opening the fibers contained in each of the pellets while heating the pellets at a temperature of 80 ° C. or higher and 140 ° C. or lower ;
A step of compressing and molding the pellets after opening to obtain a back plate.

(2) A method for manufacturing a back plate to be joined to the friction material of a brake pad including a friction material,
Preparing a pellet raw material containing resin and fibrils;
Cutting the pellet raw material to obtain a plurality of pellets containing the resin and fibers obtained by cutting the fibrils;
When the average length of the fibers contained in the pellets is 1, by opening the fibers contained in the pellets, the average length of the fibers contained in the pellets after the opening. The step of opening the fiber to set the thickness to 0.1 or more and 0.8 or less,
A step of compressing and molding the pellets after opening to obtain a back plate.

  (3) The manufacturing method of the back board as described in said (1) or (2) whose average length of the said fiber contained in the said pellet used for the process which opens the said fiber is 3 mm or more and 100 mm or less .

( 4 ) The method for producing a back plate according to any one of (1) to ( 3 ), wherein the fibers include at least one selected from the group consisting of aramid fibers, carbon fibers, and glass fibers.

( 5 ) The resin according to any one of (1) to ( 4 ), wherein the resin includes at least one selected from the group consisting of a phenol resin, an epoxy resin, a bismaleide resin, a benzoxazine resin, and an unsaturated polyester resin. Manufacturing method of back plate.

( 6 ) A back plate manufactured by the method for manufacturing a back plate according to any one of (1) to ( 5 ).

( 7 ) A brake pad comprising: a friction material; and the back plate according to ( 6 ) joined to the friction material.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the back plate which can manufacture the back plate excellent in mechanical strength easily can be provided.

Moreover, according to this invention, the back plate excellent in mechanical strength can be provided.
Moreover, according to the present invention, a highly reliable brake pad can be provided.

It is a top view which shows embodiment of the brake pad of this invention. It is a figure for showing the state where the brake pad of the present invention was arranged on the disk.

Hereinafter, the manufacturing method of the back plate, the back plate and the brake pad of the present invention will be described in detail.
1. Brake Pad First, the brake pad of this embodiment will be described.

  The brake pad of this invention is provided with the backplate manufactured by the manufacturing method of the backplate of this invention. Therefore, the brake pad of the present invention is highly reliable.

  FIG. 1 is a plan view showing an embodiment of a brake pad of the present invention, and FIG. 2 is a view for showing a state in which the brake pad of the present invention is arranged on a disc.

  The brake pad 10 is pressed against the disc during braking, and the rotation of the disc 200 can be controlled by the frictional force generated between the brake pad 10 and the disc 200.

  The brake pad 10 is composed of a joined body in which a back plate 11 and a friction material 12 are joined. In the brake pad 10, the back plate 11 and the friction material 12 may be bonded or fused (welded), and the back plate 11 and the friction material 12 may be integrated.

  In the present embodiment, the planar shape of the brake pad 10 (the friction material 12 and the back plate 11) is substantially rectangular as shown in FIG. The friction material 12 is smaller than the back plate 11 in a plan view, and is positioned so as to be included in the back plate 11 in a plan view.

  Note that, in the present embodiment, the planar shapes of the friction material 12 and the back plate 11 are each substantially rectangular, but are not limited thereto. The planar shape of the friction material 12 and the back plate 11 may be, for example, a substantially circular shape or a polygonal shape. Further, these planar shapes may be different from each other. In addition, what is necessary is just to set these planar shapes suitably according to the use of the brake pad 10. FIG.

Hereinafter, the friction material 12 and the back plate 11 constituting the brake pad 10 will be sequentially described.
[Friction material]
The friction material comes into contact with the disk during braking, and has a function of suppressing the rotation of the disk by friction caused by the contact.

  The friction material 12 abuts against the disk 200 during braking, and generates frictional heat due to friction generated between the friction material 12 and the disk 200. Therefore, it is preferable that the constituent material of the friction material 12 is excellent in heat resistance so that it can cope with frictional heat during braking. The specific constituent material is not particularly limited. For example, fiber materials such as rock wool, Kevlar fiber, copper fiber, binders such as resin, barium sulfate, zirconium silicate, cashew dust, graphite And a mixture containing the filler.

  Moreover, the average thickness of the friction material 12 is not particularly limited, but is preferably 3 mm to 15 mm, and more preferably 5 mm to 12 mm. When the average thickness of the friction material 12 is less than the lower limit value, depending on the material constituting the friction material 12, the mechanical strength is reduced, so that damage is likely to occur and the life may be shortened. Moreover, when the average thickness of the friction material 12 exceeds the said upper limit, the whole caliper apparatus provided with the friction material 12 may enlarge a little.

[Back plate]
The back plate 11 (the back plate of the present invention) is manufactured by the manufacturing method of the present invention described later, and has a hard and high mechanical strength and a high shape stability. For this reason, the back plate 11 is not easily deformed, can reliably support the friction material, and can uniformly transmit the pressing force of the piston to the friction material during braking.

The back plate 11 is composed of pellets (fiber-containing composition) containing a resin and fibers.
These components will be described in detail later.

2. Next, a preferred embodiment of the method for producing a back plate of the present invention will be described in detail.

  The manufacturing method of the back plate of the present embodiment includes a step of preparing a pellet raw material including a resin and a raw fiber (a pellet raw material preparation step), a fiber formed by cutting the pellet raw material, and the resin and the raw fiber being cut. A step of obtaining a plurality of pellets containing (pellet preparation step), a step of opening fibers contained in each pellet (opening step), and molding the obtained pellets after opening, And obtaining a step (molding step).

  The present invention is characterized by having an opening process. Thereby, the fiber contained in each pellet is unwound and resin spreads between the fibers. For this reason, the fibers can be uniformly dispersed in the finally obtained back plate. As a result, the obtained back plate exhibits excellent mechanical strength. Moreover, the dispersion | variation in the mechanical strength between the back plates obtained can also be suppressed, and the back plate of the outstanding quality can be provided.

Hereinafter, each step will be described.
[Pellet raw material preparation process]
First, a pellet raw material is prepared by coating a fibril with a resin. Here, the fibrils mean long fibers (filament bundles) and rovings (roving fibers) that are further bundled.

  As a method for coating the fibrils with resin, for example, a powder impregnation method using roving in accordance with the description in JP-T-2002-509199 can be used. The powder impregnation method using roving is a method of coating fibrils by a dry method using a fluidized bed technique. Specifically, first, other materials constituting the pellets other than the fibrils are directly applied to the fibrils from the fluidized bed without prior kneading. Next, other materials are fixed to the fibrils by heating for a short time. The fibrils thus coated are then passed through a conditioning section consisting of a cooling device and optionally a heating device. Thereby, a long pellet raw material is obtained.

[Pellet preparation process]
Next, the pellet raw material is cut into a predetermined length. Thereby, the some pellet comprised by resin and the fiber formed by cut | disconnecting a fibril is obtained. For this cutting, for example, a strand cutter is preferably used.

Therefore, a pellet is a solid material obtained by solidifying a bundle of fibers with a resin. In particular, in this embodiment, since a pellet is produced by cutting a pellet raw material, a bundle of fibers is arranged substantially in parallel in a certain direction in the pellet. By producing a pellet by such a method, the productivity of the pellet can be increased.
The resin and fiber will be described in detail later.

[Opening process]
In this step, a fiber opening process is performed on the fibers contained in the pellets. Here, the fiber opening process refers to a process of flattening the fiber bundle by applying pressure to the fiber bundle (aggregate of fibers). Examples of the fiber opening method include a method of passing pellets through a narrow gap and a method of passing pellets through a kneading unit of a uniaxial or biaxial kneader. In the following description, the opening process may be simply referred to as “opening”.

  By opening the fibers contained in each pellet, the fibers that have been hardened with resin are unraveled. At this time, a part (end portion) of the fiber is cut by an external stress resulting from the opening process, and the pellet after opening (hereinafter, also referred to as “fiber-containing composition”). Primarily, there are fibers having different lengths including main fibers and sub fibers shorter than the main fibers.

  Here, when the average length of the fiber contained in the pellet before opening is 1, the average length of the fiber contained in the pellet after opening is 0.1 or more and 0.8 or less. Is preferred. In this case, for example, it is considered that there are a large number of relatively long fibers (main fibers) having an average length of about 0.8 and a small number of short fibers (sub fibers) having an average length of about 0.1.

  In the back plate 11 manufactured using such pellets, the secondary fibers exist so as to enter the gaps between the main fibers. In other words, each fiber is present in the back plate 11 so that the gaps between the main fibers are filled with the sub fibers. As a result, the mechanical strength and shape stability of the back plate 11 are improved. In particular, when the average length of the fibers (main fibers and sub fibers) contained in the pellets after opening is within the above range, the mechanical strength and shape stability of the obtained back plate 11 are further improved. .

  Specifically, the main fiber that is longer than the secondary fiber mainly contributes to securing the mechanical strength of the back plate 11 and the shape stability of the back plate 11. On the other hand, the secondary fiber contributes to the shape stability of the back plate 11, but mainly plays a role of filling (interpolating) between the main fibers. That is, the sub fibers enter the gap between the main fibers, thereby increasing the mechanical strength of the back plate 11 in the portion where the main fibers do not exist, that is, exerting an effect of reinforcing the effect of the main fibers (reinforcing action).

  Moreover, when the method shown in the above is used to pass the pellets shown above through a narrow gap, the average length of the fibers contained in the pellets before opening (pellets used in the opening step) is determined. When it is set to 1, the average length of the fibers contained in the pellets after opening (pellets after performing the opening step) is more preferably 0.3 or more and 0.7 or less. When the average length of the fiber after opening is within such a range, the above-described interaction between the main fiber and the sub fiber can be more reliably exhibited.

  On the other hand, when the average length of the fibers after opening exceeds the upper limit, the number of main fibers becomes too large, and thus the pellet melt or softened fluidity during molding of the back plate 11. May not be sufficient. On the other hand, when the average length of the fiber after opening is less than the lower limit, the number of main fibers is too small compared to the number of sub-fibers. As a result, the reinforcing effect of the secondary fibers may not be obtained.

  Further, when the above-described method of passing the pellets through the kneading unit of the kneading machine is used as the fiber opening treatment method, when the average length of the fibers contained in the pellets before the fiber opening is 1, the fiber opening is performed. The average length of the fibers contained in the subsequent pellets is more preferably 0.1 or more and 0.6 or less.

  When the average length of the fiber after opening is within such a range, the above-described interaction between the main fiber and the sub fiber can be more reliably exhibited. On the other hand, if the average length of the fiber after opening is outside such a range, the fluidity of the melt or softened pellet may not be sufficiently obtained as described above, There is a possibility that the function of the secondary fiber is not sufficiently exhibited.

  Moreover, it is preferable to perform the fiber opening process while heating the pellet. Thereby, since resin contained in a pellet can be softened, the fiber contained in a pellet can be opened more easily and uniformly. The heating temperature is preferably 80 ° C. or higher and 140 ° C. or lower, and more preferably 90 ° C. or higher and 120 ° C. or lower. By heating the pellet at such a temperature, the resin contained in the pellet can be sufficiently softened.

  As described above, the present invention is also characterized by having a fiber opening step after the pellet preparation step. Thereby, the pellet after the opening includes the main fiber and the subfiber shorter than the main fiber. As a result, as described above, the obtained back plate 11 exhibits excellent mechanical strength and shape stability due to the interaction between the main fibers and the sub fibers. Moreover, the dispersion | variation in the mechanical strength between back boards 11 can also be suppressed, and the back board 11 of the outstanding quality can be provided.

  On the other hand, when performing a fiber opening process between a pellet raw material preparation process and a pellet preparatory process, that is, a fiber opening process is performed on the fibrils contained in the pellet raw material, and then the pellet raw material is When a pellet is produced by cutting with a length of λ, fibers of almost uniform length are included in the obtained pellet. When such pellets are used, since the effect of the interaction between the main fiber and the subfiber cannot be obtained as in the present invention, the obtained back plate 11 is compared with the back plate 11 obtained in the present invention, Mechanical strength and shape stability are lowered.

[Molding process]
In this step, the pellet (fiber-containing composition) obtained through the opening step is compression-molded to obtain the back plate 11 (the back plate of the present invention).

  By compression molding, the degree of orientation of fibers (main fibers and sub fibers) during molding can be weakened. When the main fiber and the sub fiber are oriented or non-oriented with a low degree of orientation, anisotropy in the back plate 11 can be reduced with respect to physical properties such as strength distribution, molding shrinkage, and linear expansion. Thereby, the mechanical strength and shape stability of the back plate 11 can be further improved. Further, according to compression molding, the thick back plate 11 can be easily formed, and the length of the fiber can be maintained more stably in the back plate 11. Moreover, when the back plate 11 is formed by compression molding, it is possible to reduce the loss of pellets during molding.

  According to the manufacturing method of the back plate of the present invention as described above, the fibers contained in each pellet are unwound by the fiber opening process, and the resin spreads between the fibers. For this reason, the fibers are evenly dispersed in the obtained back plate. In addition, since the pellets after opening contain fibers (main fibers and sub fibers) having different lengths, a back plate (back plate of the present invention) having excellent mechanical strength and shape stability is obtained. be able to. That is, in the back plate, each fiber is present so as to fill the gaps between the main fibers with the sub-fibers. Therefore, the obtained back plate has particularly excellent mechanical strength and shape stability.

  In addition, before shape | molding the pellet after opening in this process, the pellet after opening may be preformed and a preform may be shape | molded. That is, the manufacturing method of the back board of this invention may have the preforming process with respect to the pellet after fiber opening. Thereby, the handleability of the pellet after opening is improved. As a result, the productivity of the back plate can be further improved.

  Moreover, you may heat-process in advance with respect to the pellet after opening before a shaping | molding process. That is, the manufacturing method of the back plate of the present invention may have a preheating step for the pellets after opening. Thereby, the moldability (ease of forming) of the pellets after opening can be further improved. As a result, the productivity of the back plate 11 can be improved.

  The method for manufacturing the brake pad 10 is not particularly limited, and examples thereof include a method of pasting the friction material 12 after the back plate 11 is formed, a method of integrally forming the back plate 11 and the friction material 12, and the like. .

3. Pellet Next, the pellet will be described in detail.

As described above, the pellet includes the resin and the fiber.
Hereinafter, each component will be described in detail.

[resin]
The pellet includes a resin.

  In the present embodiment, the resin may be in any form such as solid, liquid, and semisolid at room temperature.

  Examples of the resin include a curable resin such as a thermosetting resin, a photocurable resin, a reactive curable resin, and an anaerobic curable resin. Among these, since it is excellent in mechanical characteristics such as linear expansion coefficient and elastic modulus after curing, a thermosetting resin is preferable.

  Examples of thermosetting resins include phenolic resins, epoxy resins, bismaleide resins, urea (urea) resins, melamine resins, polyurethane resins, cyanate ester resins, silicone resins, oxetane resins, (meth) acrylate resins, unsaturated polyester resins. , Diallyl phthalate resin, polyimide resin, benzoxazine resin and the like, and one or more of them can be used in combination. Among these, especially as a thermosetting resin, a phenol resin, an epoxy resin, a bismaleide resin, a benzoxazine resin, and an unsaturated polyester resin are preferable, and a phenol resin is more preferable. Thereby, the molded article can exhibit excellent heat resistance.

  Examples of the phenol resin include novolak type phenol resins such as phenol novolak resin, cresol novolak resin, bisphenol A novolak resin, arylalkylene type novolak resin; unmodified resole phenol resin, tung oil, linseed oil, walnut oil Examples include resol-type phenol resins such as oil-modified resol phenol resins, and one or more of them can be used in combination. Among these, as the phenol resin, a phenol novolac resin is particularly preferable. Thereby, while being able to manufacture a molded article with low cost and high dimensional accuracy, the obtained molded article can exhibit the especially outstanding heat resistance.

  Although the weight average molecular weight of a phenol resin is not specifically limited, About 1,000-15,000 are preferable. If the weight average molecular weight is less than the lower limit, the viscosity of the resin may be too low to make it difficult to prepare pellets. If the upper limit is exceeded, the resin will have a higher melt viscosity. The moldability (easiness of molding) may be reduced. The weight average molecular weight of the phenol resin is measured by, for example, gel permeation chromatography (GPC) and can be defined as a weight molecular weight in terms of polystyrene.

  Epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AD type epoxy resins and other bisphenol type epoxy resins; phenol novolac type epoxy resins, cresol novolac type epoxy resins and other novolak type epoxy resins; Brominated epoxy resins such as A-type epoxy resins and brominated phenol novolac-type epoxy resins; biphenyl-type epoxy resins; naphthalene-type epoxy resins; tris (hydroxyphenyl) methane-type epoxy resins, etc., one of these Alternatively, two or more kinds can be used in combination. Among these, as the epoxy resin, bisphenol A type epoxy resin, phenol novolak type epoxy resin, and cresol novolak type epoxy resin having a relatively low molecular weight are particularly preferable. As a result, the fluidity of the pellet melt or softened material can be improved, so that the pellet melt or softened material can be handled and formed easily (easiness of molding) during the production of the molded product. can do. From the viewpoint of further improving the heat resistance of the molded product, the epoxy resin is preferably a phenol novolac type epoxy resin or a cresol novolac type epoxy resin, and particularly preferably a tris (hydroxyphenyl) methane type epoxy resin.

  The bismaleimide resin is not particularly limited as long as the resin has maleimide groups at both ends of the molecular chain, but a resin having a phenyl group is more preferable. Specifically, for example, a resin represented by the following formula (1) can be used. However, the bismaleimide resin may have maleimide groups that bind to positions other than both ends of the molecular chain.

In formula (1), R ^{1 to} R ⁴ are hydrogen or a substituted or unsubstituted hydrocarbon group having 1 to 4 carbon atoms, and R ⁵ is a divalent substituted or unsubstituted organic group. Here, the organic group is a hydrocarbon group that may contain a heteroatom, and examples of the heteroatom include O, S, and N. R ⁵ is preferably a hydrocarbon group having a main chain in which a methylene group, an aromatic ring, and an ether bond (—O—) are bonded in any order, and more preferably methylene bonded in any order in the main chain A hydrocarbon group having a total number of groups, aromatic rings and ether bonds of 15 or less. In the middle of the main chain, a substituent and / or a side chain may be bonded, and specific examples thereof include, for example, a hydrocarbon group having 3 or less carbon atoms, a maleimide group, a phenyl group, and the like. It is done.

  Specifically, as the bismaleimide resin, for example, N, N ′-(4,4′-diphenylmethane) bismaleimide, bis (3-ethyl-5-methyl-4-maleimidophenyl) methane, 2,2- Bis [4- (4-maleimidophenoxy) phenyl] propane, m-phenylenebismaleimide, p-phenylenebismaleimide, 4-methyl-1,3-phenylenebismaleimide, N, N′-ethylenedimaleimide, N, N '-Hexamethylene dimaleimide and the like can be mentioned, and one or more of these can be used in combination.

  The content of the resin in the pellet (back plate 11) is not particularly limited, but is preferably 20% by mass or more and 80% by mass or less, and more preferably 30% by mass or more and 50% by mass or less. When the resin content is less than the lower limit, depending on the type of resin, the binding strength with other materials (particularly fibers) constituting the pellet (back plate 11) may not be sufficiently obtained. Moreover, when the content rate of resin exceeds the said upper limit, the quantity of the fiber mentioned later reduces relatively and the effect of including a fiber may not fully be exhibited.

[fiber]
The pellet contains fibers.

  The average length of the fibers contained in the pellets subjected to the opening process is preferably 3 mm or more and 100 mm or less, and more preferably 5 mm or more and 60 mm or less. Thereby, the mechanical strength of the back plate 11 finally obtained can be further improved. On the other hand, when the average length of the fiber is less than the lower limit, the shape stability of the back plate 11 may not be sufficiently obtained depending on the constituent material of the fiber and its content. In addition, when the average length of the fibers exceeds the above upper limit, the fluidity of the pellet melt or softened product may not be sufficiently obtained when the back plate 11 is formed.

  On the other hand, the pellet after opening contains a main fiber and a sub-fiber shorter than the main fiber. Thereby, the moldability (ease of molding) of the back plate is improved, and the molded back plate has increased mechanical strength and shape stability.

  The average length L1 of the main fibers is preferably 3 mm or more and 90 mm or less, more preferably 5 mm or more and 50 mm or less, and further preferably 8 mm or more and 12 mm or less. When the average length L1 of the main fiber is less than the lower limit value, the shape stability of the back plate may not be sufficiently obtained depending on the constituent material of the main fiber and its content. Further, when the average length L1 of the main fibers exceeds the upper limit, the fluidity of the pellet melt or softened product may not be sufficiently obtained during the molding of the back plate.

  Further, the average length L2 of the auxiliary fibers is preferably 0.1 mm or more and 10 mm or less, more preferably 0.3 mm or more and 5 mm or less, and further preferably 0.5 mm or more and 3 mm or less. When the average length L2 of the secondary fibers is less than the lower limit, for example, when the main fiber content is low, the secondary fibers in the pellets after opening are used to increase the reinforcing effect of the effect of the primary fibers. It may be necessary to relatively increase the content of. Moreover, when the average length L2 of a subfiber exceeds the said upper limit, when there is much content rate of a main fiber, the ratio which a subfiber enters in the clearance gap between main fibers falls.

  The average diameter of the fibers (main fibers and sub fibers) is preferably 5 μm or more and 20 μm or less, more preferably 6 μm or more and 18 μm or less, and further preferably 7 μm or more and 16 μm or less. When the average diameter of the fiber is less than the lower limit value, the fiber is likely to be damaged when the back plate 11 is formed depending on the constituent material and content of the fiber. Moreover, when the average diameter of the fiber exceeds the upper limit, the formability may be lowered depending on the constituent material of the fiber and its content.

  The cross-sectional shape of the fibers (main fibers and sub fibers) is not particularly limited, but any shape such as a substantially circular shape such as a circle and an ellipse, a polygon such as a triangle, a rectangle and a hexagon, a flat shape, a deformed shape such as a star, etc. It may be a shape. Among these, the cross-sectional shape of the fiber is particularly preferably substantially circular or flat. Thereby, the smoothness of the surface of the back plate 11 can be improved. Moreover, the handling property at the time of shaping | molding of the molten material or softened material of a pellet improves more, and the moldability becomes further favorable.

  Examples of the fibers (main fibers and auxiliary fibers) are organic fibers such as aramid fibers, acrylic fibers, nylon fibers (aliphatic polyamide fibers) and phenol fibers, glass fibers, carbon fibers, ceramic fibers, rock wool, titanium, respectively. Examples include inorganic fibers such as potassium acid fibers and basalt fibers, and metal fibers such as stainless fibers, steel fibers, aluminum fibers, copper fibers, brass fibers and bronze fibers, and one or more of these are combined. Can be used. Among these, the fibers are more preferably aramid fibers, carbon fibers, and glass fibers, respectively.

  When glass fiber is used, the uniformity of the pellet melt / softened product per unit volume is improved, and the moldability of the fiber-containing composition is particularly good. Furthermore, by improving the uniformity of the pellet melt or softened material, the uniformity of the internal stress in the formed back plate 11 is improved, and as a result, the undulation of the back plate 11 is reduced. Moreover, the abrasion resistance of the back plate 11 under a high load can be further improved. Further, when carbon fiber or aramid fiber is used, the mechanical strength of the back plate 11 can be further increased, and the back plate 11 can be further reduced in weight.

  Specific examples of the glass constituting the glass fiber include, for example, E glass, C glass, A glass, S glass, D glass, NE glass, T glass, and H glass. Among these, as glass constituting the glass fiber, E glass, T glass, or S glass is particularly preferable. By using such glass fibers, it is possible to achieve high elasticity of the fibers (main fibers and sub fibers) and to reduce the thermal expansion coefficient thereof.

  Specific examples of the carbon fiber include high-strength carbon fiber having a tensile strength of 3500 MPa or more and high-modulus carbon fiber having an elastic modulus of 230 GPa or more. The carbon fiber may be either a polyacrylonitrile (PAN) -based carbon fiber or a pitch-based carbon fiber, but is preferably a polyacrylonitrile-based carbon fiber because of its high tensile strength.

Moreover, the aramid resin which comprises an aramid fiber may have any structure of a meta type structure and a para type structure.
Moreover, it is preferable that the fiber is surface-treated beforehand.

  By performing the surface treatment in advance, the fiber can increase the dispersibility in the fiber-containing composition, increase the adhesion with the resin, and the like.

  Examples of such surface treatment methods include coupling agent treatment, oxidation treatment, ozone treatment, plasma treatment, corona treatment, and blast treatment, and one or more of these may be combined. Can be used. Among these, a coupling agent treatment is particularly preferable as the surface treatment method.

  The coupling agent used for the coupling agent treatment is not particularly limited and can be appropriately selected depending on the type of resin.

  Examples of the coupling agent include a silane coupling agent, a titanium coupling agent, and an aluminum coupling agent, and one or more of these can be used in combination. Among these, a silane coupling agent is particularly preferable as the coupling agent. Thereby, especially the adhesiveness with respect to resin (curable resin) improves a fiber.

  Silane coupling agents include epoxy silane coupling agents, cationic silane coupling agents, amino silane coupling agents, vinyl silane coupling agents, mercapto silane coupling agents, methacryl silane coupling agents, chlorosilane coupling agents, and acrylic silanes. A coupling agent etc. are mentioned.

  The content of the fiber in the pellet (fiber-containing composition) is preferably 20% by mass or more and 80% by mass or less, and more preferably 30% by mass or more and 70% by mass or less. Thereby, the mechanical strength of the obtained back plate 11 can be improved more efficiently.

[Other ingredients]
The pellets are further optionally hardeners, curing aids, fillers, mold release agents, pigments, sensitizers, acid multipliers, plasticizers, flame retardants, stabilizers, antioxidants and antistatic agents. Etc. may be included.

  A hardening | curing agent can be suitably selected and used according to the kind etc. of resin, and is not limited to a specific compound.

  For example, when a phenol resin is used as the resin, the curing agent can be selected from bifunctional or higher epoxy compounds, isocyanates, hexamethylenetetramine, and the like.

  When an epoxy resin is used as the resin, the curing agent may be an acid anhydride such as an amine compound such as an aliphatic polyamine, aromatic polyamine or diciamine diamide, an alicyclic acid anhydride, or an aromatic acid anhydride. Products, polyphenol compounds such as novolac type phenol resins, imidazole compounds and the like. Among these, from the viewpoint of handling workability and environment, it is preferable to select a novolac type phenol resin as a curing agent.

  In particular, when a phenol novolac type epoxy resin, a cresol novolac type epoxy resin, or a tris (hydroxyphenyl) methane type epoxy resin is used as the epoxy resin, it is preferable to select and use a novolac type phenol resin as a curing agent. . Thereby, the heat resistance of the back plate 11 can be improved.

  In the case of using a curing agent, the content of the curing agent in the pellet (fiber-containing composition) is appropriately set depending on the type of the curing agent and the resin to be used, for example, 0.1% by mass to 30% by mass. The following is preferable. Thereby, the back board 11 can be easily formed in arbitrary shapes.

  Moreover, it does not specifically limit as a hardening adjuvant, For example, an imidazole compound, a tertiary amine compound, an organic phosphorus compound etc. can be used.

  When a curing aid is used, the content of the curing aid in the pellet (fiber-containing composition) is appropriately set depending on the type of the curing aid and the curing agent to be used. For example, 0.001% by mass The content is preferably 10% by mass or less. Thereby, since a pellet (fiber containing composition) can be hardened more easily, the back board 11 can be shape | molded more easily.

  Further, the filler is not particularly limited, and examples thereof include inorganic fillers and organic fillers. Examples of the inorganic filler include calcium carbonate, clay, silica, mica, talc, wollastonite, glass beads, milled carbon, graphite, and the like, and one or more of these may be used in combination. Can do. Examples of the organic filler include polyvinyl butyral, acrylonitrile butadiene rubber, pulp, wood powder, and the like, and one or more of these can be used in combination. Among these, it is preferable to use acrylonitrile butadiene rubber as a filler (organic filler) from the viewpoint that the effect of improving the toughness of the back plate 11 is further enhanced.

  When the filler is used, the content of the filler in the pellet is not particularly limited, but is preferably 1% by mass or more and 30% by mass or less. Thereby, the mechanical strength of the back plate 11 can be further improved.

  Moreover, as a mold release agent, although it does not specifically limit, a zinc stearate, a calcium stearate, etc. can be used.

  When a release agent is used, the content of the release agent in the pellet is not particularly limited, but is preferably 0.01% by mass or more and 5.0% by mass or less. Thereby, the backplate 11 can be easily formed by arbitrary shapes.

  As a method for preparing pellets, for example, a powder impregnation method using roving in accordance with the description in JP-T-2002-509199 can be used.

The powder impregnation method using roving is a method of coating fibers by a dry method using a fluidized bed technique. Specifically, first, a material such as a resin other than the fibers is directly applied to the fibers from the fluidized bed without prior kneading. Next, a material such as a resin is fixed to the fiber by heating for a short time. The coated fiber is then passed through a conditioning section consisting of a cooling device and possibly a heating device. Thereafter, the cooled and coated fiber is taken up and cut to a desired length by a strand cutter. Thereby, a pellet is obtained.
As mentioned above, although preferred embodiment of this invention was described, this invention is not limited to this.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example and a comparative example, this invention is not limited to this.

<1> Production of back plate (Example 1)
[1] Preparation of pellets Pellets were prepared as follows.

  First, 55.0% by mass of glass fiber (PPG glass fiber roving 1084, average diameter: 15 μm) surface-treated with a silane coupling agent as a fiber fibril was prepared.

  Next, 36.0% by mass of phenol resin (Sumitite Bakelite Co., Ltd. Sumitrite Resin PR-51470, weight average molecular weight: 2800) as resin, 6.0% by mass of hexamethylenetetramine as curing agent, and curing A resin mixture is obtained by mixing 1.0% by mass of magnesium oxide as an auxiliary agent, 1.0% by mass of calcium stearate as a release agent, and 1.0% by mass of carbon black as a pigment. It was.

  Next, the obtained resin mixture was coated on the surface-treated glass fiber using a fluidized bed technique, melted and fixed by a heater heated to 400 ° C., and then cooled.

  Next, the glass fiber coated with the resin mixture was cut with a strand cutter so that fibers having an average length of 20 mm were obtained. Thereby, a pellet was obtained.

[2] Opening step The obtained pellets are subjected to a fiber-opening treatment while being heated to 100 to 110 ° C with a uniaxial kneader (manufactured by Imoto Seisakusho Co., Ltd., product name "IMC-1894 type"). Pellets (fiber-containing composition) were obtained.

[3] Production of Back Plate A back plate was produced as follows using the obtained pellets (fiber-containing composition) after opening.

  First, pellets (fiber-containing composition) after opening were put into a mold heated to 80 to 90 ° C., and compressed by a conventional method to prepare a preform. The preform had a length of 110 mm, a width of 45 mm, a height of 8 mm, and a weight of 60 g.

  Next, the preform was preheated to 100 to 110 ° C. by a parallel plate type high frequency preheater. This preheated preform was put into a mold, pressurized and heat-cured to obtain a back plate having a length of 130 mm × width of 50 mm × thickness of 6 mm. The molding conditions were a mold temperature of 170 to 180 ° C., a molding pressure of 20 to 25 MPa, and a curing time of 3 minutes.

(Examples 2 to 13)
A back plate was produced in the same manner as in Example 1 except that the configuration of the pellets was changed as shown in Table 1.

(Comparative Example 1)
A back plate was produced in the same manner as in Example 1 except that the [2] fiber opening step of Example 1 was not performed and the pellets were used as a “fiber-containing composition” in the production of [3] back plate.

  In the table, fibers obtained from glass fibers (PPG glass fiber roving 1084, average diameter D1: 15 μm) are “glass 1”, carbon fibers (Toho Tenax Co., Ltd. carbon fiber roving HTS40, average diameter D1: 7 μm). The fiber obtained from "Carbon 1", Magnesium oxide as the curing aid "Z1", Clay as the filler "J1", Milled carbon as the filler "J2", Graphite as the filler Shown as “J3”.

<2> Evaluation of back plate (bending strength)
A part having a size of length 80 mm × width 10 mm × thickness 4 mm with respect to the traveling direction of the disc was cut out from the center of the back plate of each example and comparative example to obtain a test piece for measuring the bending strength. . The bending strength of this test piece was measured according to ISO 178 and evaluated according to the following criteria.

A: The bending strength is 140 MPa or more.
B: Bending strength is 120 Mpa or more and less than 140 Mpa.
C: Bending strength is 100 Mpa or more and less than 120 Mpa.
D: Bending strength is 80 Mpa or more and less than 100 Mpa.
E: Bending strength is less than 80 Mpa.
The results are shown in Table 1.

  As is clear from Table 1, the back plate of each example according to the present invention had good moldability. Moreover, it was excellent in bending strength. On the other hand, in the comparative example, a satisfactory result was not obtained.

10 Brake pads 11 Back plate 12 Friction material 200 Disc

Claims (7)

A manufacturing method of a back plate joined to the friction material of a brake pad including a friction material,
Preparing a pellet raw material containing resin and fibrils;
Cutting the pellet raw material to obtain a plurality of pellets containing the resin and fibers obtained by cutting the fibrils;
Opening the fibers contained in each of the pellets while heating the pellets at a temperature of 80 ° C. or higher and 140 ° C. or lower ;
A step of compressing and molding the pellets after opening to obtain a back plate.   A manufacturing method of a back plate joined to the friction material of a brake pad including a friction material,
  Preparing a pellet raw material containing resin and fibrils;
  Cutting the pellet raw material to obtain a plurality of pellets containing the resin and fibers obtained by cutting the fibrils;
  When the average length of the fibers contained in the pellets is 1, by opening the fibers contained in the pellets, the average length of the fibers contained in the pellets after the opening. The step of opening the fiber to set the thickness to 0.1 or more and 0.8 or less,
  A step of compressing and molding the pellets after opening to obtain a back plate.   The method for producing a back plate according to claim 1 or 2, wherein an average length of the fibers contained in the pellets provided for the step of opening the fibers is 3 mm or more and 100 mm or less. The said board | substrate is a manufacturing method of the backplate of any one of Claim 1 thru | or 3 containing at least 1 sort (s) selected from the group which consists of an aramid fiber, carbon fiber, and glass fiber. The said resin contains at least 1 sort (s) selected from the group which consists of a phenol resin, an epoxy resin, a bismaleide resin, a benzoxazine resin, and an unsaturated polyester resin, The manufacture of the backplate of any one of Claim 1 thru | or 4 Method. A back plate manufactured by the method for manufacturing a back plate according to any one of claims 1 to 5 . A brake pad comprising: a friction material; and the back plate according to claim 6 joined to the friction material.

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