JPS5949239A - Extrusion coating continuous tape - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to facings for friction clutches, and more particularly to an extrusion coated continuous tape suitable for the manufacture of facings for friction clutches.

The continuous tape consists of at least one continuous strand or filament extrusion coated with a curable binder composition. Continuous tapes are rolled into preforms and heat cured under pressure to create extremely good visibility.
rst) adapted to form an asbestos-free clutch facing that exhibits strength.

Due to its high heat resistance, asbestos has long been used as the main support for friction elements, especially in the automotive industry. When used as a suitable friction resin composition, a highly satisfactory friction element is obtained. However, recently health risks associated with the manufacture and use of asbestos-containing compositions and articles have been revealed. As a result, efforts have increased to develop asbestos-free compositions for use in the manufacture of friction elements. The use of glass fibers in such alternative compositions is well known in the prior art, such as U.S. Pat. No. 3,743. O'69, 4.130,5
No. 37 and No. 4,137,214. In the prior art compositions of Jl et al., the glass fibers are included in chopped fiber form or as continuous strands. When using glass fibers in the form of continuous strands, the glass fibers I are usually sized and then impregnated with a friction resin composition, 11. 1. The strands are usually coated by dip coating, i.e. first the friction resin thread E't'
It is impregnated by passing the strand through a dipping bath containing a dilute solution or dispersion (cement) of ytate. The wet, impregnated strand is then passed through a drying tower or other device to evaporate the solvent and produce a dry, uncured, cement-impregnated strand. The strands are used to wind to form a preform, which is then heat cured under pressure by well known techniques to produce a single cured friction element.

Dip coating methods for impregnating continuous strands generally involve a substantial amount, often greater than 50 parts of the total composition.
It is necessary to use a cement containing a solvent to adequately penetrate the strands as well as to prepare a cement with a viscosity suitable for use in coating equipment. When the cement is a dispersion or contains dispersed solids, sedimentation or separation of the solid components in the soaking bath can be a problem.3 Furthermore, Cement I-impregnated strands must be dried to make them suitable for use. ablation requires the use of drying towers or other drying equipment. To meet even more restrictive environmental regulations, the solvent removed in the drying process will typically be recovered by sophisticated, expensive solvent recovery equipment and then recycled. These drying and solvent recovery steps add considerably to the overall production cost. Thus, a substantial reduction or elimination of solvent use in the manufacture of clutch phase songs would provide substantial benefits.

The present invention is a continuous tape suitable for use in the manufacture of friction clutch facings, said tape comprising at least one strand or filament extrusion coated with a thermoset friction resin composition. This continuous tape can be used in the construction of cladding that exhibits extremely high burst strength, and the method of manufacturing said tape eliminates or substantially reduces the use of solvents for friction resin compositions. 3.'A continuous tape made in accordance with the technique of the present invention consists of at least one continuous strand or filament extrusion coated with a friction resin composition.

Continuous strands or filaments useful in the practice of the present invention can be made from any of the known reinforcing fibers, such as glass, cotton, graphite, aramid, etc., as well as combinations of two or more of these fibers. can also be formed. Preferably, the continuous strands will be formed from glass fibers, 11 and treated with a coupling agent to enhance resin adhesion in accordance with well known practice in the art. The strand is
Preferably (7) well known in the art, e.g., U.S. Pat.
9 2 5.2 8 As shown in the specification of No. 6"1,
The methods and compositions can be used to prepare sizing agents, such as N
It is sized by impregnation with FL coating latex.

The friction resin composition can be any of the thermosetting and rubber-modified resin compositions commonly used in the manufacture of friction elements. , standard compositions usually combine curable phenolic resins, i.e., thermosetting resins derived from phenols and aldehydes, with rubber modifiers, such as natural rubber or rubbery polymers such as chloroprene, butadiene, inobrene, etc. or one or more monomers copolymerizable with those monomers, e.g.
Acrylates, methacrylates or other alkyl acrylates may be included together with copolymers of acrylonitrile, styrene, alpha methylstyrene, ethylene, propylene, vinylpyridine, and the like.

The composition may further include other additives, such as vulcanizing agents, accelerators, crosslinking agents, friction modifiers, etc., according to well known practice and practice.

fillers, e.g. carbon black, graphite,
Clays and the like may also be included, as well as chopped inorganic or organic fibers, such as wollastonite, aramid fibers, glass fibers. Such IV rub compositions are generally well known in the art.

A continuous strand is extrusion coated with a friction resin composition. Any method known in the art of extrusion coating of wire can be used for the purpose of the present invention.

An example of a machine for extrusion coating wire with a viscous pasty material is disclosed and described in US Pat. No. 2,315,645 and uses a trigger coating die.

Alternatively, the continuous filament or strand can be passed through a wire-coated die fed by a conventional extruder. It has been widely used for wire coating. One or more variations can be used to coat continuous strands or filaments, including continuous calendering.

The friction resin composition is applied at room temperature or at an elevated temperature below the curing temperature of the particular resin used. When the viscosity of a friction resin composition is too high for satisfactory coating, even at elevated temperatures, it may be desirable to dilute the resin composition with a small amount of solvent to reduce the viscosity and improve coating speed. Dew. The strand exiting the extrusion die is thus coated with an uncured, substantially dry friction resin composition.

One or more strands of gold can be coated simultaneously to form a tape using an extrusion coating process. When coating multiple strands, the strands are spaced apart and exit the extrusion coating equipment in a flat ribbon die.

In the manufacture of clutch facings, the tape of the present invention is fed to a winding device and wound into a playform. A preform is also an article of loose structure impregnated with a curable resin composition in an uncured or partially cured state, and also composed of reinforcing components that are woven or wound. . In one method of forming a preform, one or more extrusion-coated tapes are helically wound in face-to-face relationship to form turns of desired size or weight, or annular discs. Form a preform. A second technique for forming preforms is to cam the covering tape in a corrugated pattern to the desired size, as shown, for example, in U.S. I. Patent No. 3,600,258. and to form an annular disc preform of weight.

The preform is then heated and pressed to produce a hardened friction element according to methods well known in the art. .

The following examples further illustrate the implementation of the invention.

Example 1 16% Ft 1% elastomer and 26.6% by weight
A friction resin composition consisting of a phenolic resin, an inorganic filler, a hardening aid, a thickener, and graphite was extrusion coated onto a sized glass fiber strand. Extrusion coating is carried out by extruding the resin composition by passing a strand of fiber through a wire coating extrusion die fed by a Brabender extruder at a barrel temperature of 95°F (35°C). did. The coated strands or tapes consisted of 35 weight parts glass fiber (average) and 65 weight parts partially cured resin composition.

The tape was cam-wound to form a 7-A/L preform for the clutch. Use this preform as a mold for 200
Place under pressure of 0ps<(140Kq/crl), 35
Heat at 0°F (177°C) for 5 minutes, then below 400°C (
It was post-cured for 5 hours at 20.4°C.

Hardened J also clutch facing is 13,100R
/' It had a burst strength of AI (half cut).

Example 2 20.7 weight parts of Nidistomer and 10.8 weight parts of phenolic resin were mixed with inorganic fillers, curing agents, friction modifiers and chopped (0.25 in., 0.64 cn.
r) fluffy aramid fiber (Kevl from DuPont)
A friction resin composition was prepared containing AQ fiber (obtained as AQ fiber). This composition was mixed with methyl ethyl ketone to reduce the viscosity and coated at 90°C (32°C) using a wire extrusion coating die attached to a Brabender extruder.
was extruded onto a strand of glass fiber to form a tape. This 7-piece was wound with a cam to form a brefuono of a taracci faizon. The preform was air dried to remove the solvent and then placed in a mold at 2000 ps.
Entered under pressure of i (140Ky/cnf) J1.3
The preform was cured by heating to 50'F (177C) for 5 minutes.

This facing was then heated to 400'F (204°C
1, cured Thalasso Fa 7, which was post-cured for 5 hours under a pressure of 500 psi (35 to 9/cnl), had an average burst strength of 1,300, Rp M.

Example 3 The friction resin composition of Example 1 was used to extrusion coat four parallel glass fiber strands simultaneously. Here, the strands were passed through a cylindrical die having a flat ribbon die at the outlet and fed into a Brabender extruder. The resulting flat tape was used to form a cam-wound preform, which was then rolled to 2000 psj (14
0Kg/c# pressure TIF3FI (1 below (177℃)
and cured as before to produce a friction tart facing.

Example 4. .

15.5% by weight Nidistomer, 8.0% by weight phenolic resin, 19.3% by weight chopped glass fibers and 5.5% by weight aramid fibers (obtained as dried Kevlar aramid bulbs from EI DuPont). ), along with inorganic fillers, curing agents, and friction modifiers, were prepared by dry powder formulation. This powder formulation was fed directly to a Brabender extruder and extruded through a ribbon die at 210°C (99°C). This J9 demonstrated the ease of extrusion of this composition.

As can be seen from this example, a continuous strand or filament is extrusion coated with a friction resin composition to produce a preform to produce a friction tarp suspension having excellent burst strength properties. A tape suitable for use in filament winding can be formed. The friction resin composition can be used directly for extrusion (Example 1) or mixed with a solvent as in Example 2 to change the viscosity of the resin. The resulting tape does not require any further drying before use in winding preforms. If a solvent is used to modify the extrusion viscosity of the resin, the resulting tape can be rolled into a preform without drying.

The preform is then dried in less complex equipment that facilitates solvent recovery, thus reducing solvent recovery;
The cost factors associated with point 9 can be improved.

Chopped aramid fiber (Example 2) or aramid 1-
Inclusion of short fibers such as Valve (Example 4) significantly improves the wear properties of the resulting friction element.
The use of chopped fibers (Example 2) required the inclusion of additional solvent to reduce the viscosity of the friction resin composition to a level suitable for extrusion coating. When used in pulp form, the friction resin composition could be easily extruded without using solvent. Suitable tapes can be readily produced by the method of the present invention using pulp of aramid fibers in the friction resin composition.As can be seen, tapes are made of a curable friction resin composition according to the present invention. A continuous tape is obtained which is suitable for use in the manufacture of friction clutch facings, consisting of strands of extrusion coated σJ and continuous fibers.

% Applicant: Bork Warner Corp./
Agent: Patent Attorney Kyo Yuasa, 3rd I (3 others)

Claims (1)

[Scope of Claims] 1. A thermosetting rubber modified resin composition selected from the group consisting of chopped aramid fibers and aramid fiber valves.
a continuous fiber adapted for use in the preform of a wound friction element, characterized in that it consists of at least one continuous glass fiber extrusion coated with a curable friction resin composition comprising 12, 14' + j strands of glass fibers (- means the continuous tape according to claim 1, wherein - is coated with a nydistomer before extrusion coating. a) The continuous tape according to claim 1, wherein the fibers are aramid fibers. 1st
Continuous tape as described in section. 4. The continuous tape according to claim 1, wherein the fibers are aramid fiber pulp.