DE2452407A1 - MODIFIED HEAT RESINS - Google Patents

Description

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~ PATENT Attorney 2452407

DipL-In «. P. WiRTH Dr. V. SCHMIEO-KOWARZIK DipL-lng. G. DANNENEERG Dr. P. WEINHOLD Dr. D. GUOEL

281134 6 FRANKFURT AM

phone <oem

287014 «Π. EeCUENHEIWen 8THACSt! 39

Dr Ha / Fr.

Oasis Pia 3607

BP CHEMICAiS Ii ^ JbBJiAIlQHAi LIMI'XED Britannic House
Moor Lane

London SC 2 Y 9BU
England

¹¹ Modified thermosetting resins "

The present invention relates to modified phenolic resins for use in the manufacture of Friction elements and friction elements O made therefrom

Friction members such as clutch plates and brake pads can be made by bonding a friction material with a resin. Usually asbestos is used as a friction material, either a woven structure or 3 <'aserformc The Eeibungsinaterialien usually with a hitzehärfcbaren Plienolharz connected \ / hen such ReibungesleipentG hard Breais- or Xupplungs-

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BATH ORIGINAL

are subjected to operating conditions, they tend as a result or high temperatures to disturb the friction elements, ·. resulting in wear and / or loss of the frictional properties.

There have already been Binderharae _s by using previously prepared phenylborates hand out of phenol had been made, proposed for improving the Hochueraperatur-Eigenschaf'tcn of friction members' AUSS phenylborates formed. Resins, however, are difficult to manufacture. It has also been proposed to add boric acid or oxides to preformed ITovolak resins, but it is difficult to incorporate larger amounts of boron: either a heterogeneous mixture is obtained, or - if attempted - the. Boric acid or-oxide after ^ll cook-in "-Kethode is to process the melt viscosity is too high or it will gel formation takes It has also been proposed to incorporate Orthoborsäureester in phenolic resins;. However, the addition of such esters to provide the necessary amounts of boron add, the softening point of the resin is lowered, with the result that it can no longer be easily ground more than $ 0.5) to introduce boron into the reaction mixture before gel formation takes place, _etc.

The object of the present invention is the manufacture of new phenolic resins modified by boron (both from lovolak and of the resol type) for use as binder resins in friction elements ο

According to the present invention, the binder resin for the Manufacture of friction elements from a phenolic resin with or containing a metaborate of the empirical form! .ROBO, where pure-JSLkyl-, alkenyl-, cycloalkyl- or aryl-

509819/1174

Means hydrocarbon radical, # give in a sufficient amount to the entire binder resin has a boron content of about 0.5 to 3 _f0. ~.

In the present invention, any phenolic resin of the known type can be used as a resin for friction and elements. For example, a high-quality resin can be produced by reacting a monohydric or dihydric phenol and an aldehyde under the conditions of Novolsk or Reeolreeition will. The phenolic resin is preferably produced from phenol per se (CgH ₁ -OH) and Fooaaldetiya. Iodoeh can also be phenol / aldehyde from cresol, xylenol or other alkyl- or aralkyl-substituted phenols, resorcinol or aca; jounuss (cashew-nut) shale liquid instead of all or part of the phenol and furfural, Acetaldehyde or benzaldehyde can be used in place of all or part of the aldehyde. The phenolic resins can be modified by known methods with other substances such as natural or synthetic rubber, fatty oils, fatty acids or epoxy resins.

Novolak resins are usually used under acidic conditions a molar excess of phenol. Also for use in the compositions of the invention are Resins suitable as higher Ortho-ETovolak ("high ortho novolaks ") are known and which by reacting a molar excess = in phenol with an aldehyde using certain alkaline catalysts, e.g. zinc acetate, magnesium hydroxide or barium formate.

Reeo3harze are made in the presence of alkaline catalysts made with a molar excess of aldehydes »

Those in the resin compositions of the present invention Metaborates used have the empirical formula POBO,

509819/1174 bad original

where R is a. Alkyl, cycloalkyl, or ary! Hydrocarbon rest can be. Alkyl and alkenyl radicals with 1 to 18 carbon atoms are preferred » Examples include methyl, ethyl, butyl and stearyl as alkyl substituents and vinyl, allyl, hexenyl and Dodecenyl as alkenyl substituents. R is particularly preferably a medrigalkyl group with about 1 to 6 carbon atoms.

Suitable cycloalkyl radicals have about 5 to 18 carbon atoms, preferably about 5 to 8 carbon atoms * For example are called the cyclohexyl and cyclooctyl groups !.

Suitable aryl radicals have about 6 to 18 carbon atoms ^, preferably about 6 to 10 carbon atoms. For example be called the Phenyl-, Benzyl-, Tolyl-, Phenyläthyl-, XyIyI-, Naphthyl and hexylphenyl group.

Although the metaborates have the empirical formula ROBO, it is believed that they are in the trimeric form of the general formula

RO

RO. ^X OR

occurrence.

The metaborates (boroxines) used in the binder resin compositions of the present invention can be prepared by known methods; for example by heating orthoboric acid or metaboric acid with equimolar amounts of alcohol or phenol with removal of the water of reaction, by heating boron oxide mii; dimol & ren Uengen alcohol, or phenol under BnI-

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BAB OfiiQiNAL

removal of the water of reaction or by treatment of trialkoxy or iriaryloxyboranes with orthoboric acid, metaboric acid or boron oxide.

The metaborates used in the phenol aldehyde resins according to the invention can be obtained directly from the above-mentioned reaction mixtures obtained or isolated by known methods. You can use smaller amounts of other boron compounds e.g. orthoboric acid »orthoborates, boron oxides or polyborates.

The amount of metaborate in the binder resin composition should be sufficient to have a boron content of about 0.5 to 3.0% by weight in the final resin product, preferably of about 1.0 to 2.0 Wt .- $ to yield »

If an apparently homogeneous product can easily be made, the phenol bara is conveniently mixed with the metaborate in the molten state. The presence of the metaborate does not significantly lower the softening point of the resin, and the final product can be ground using known procedures to obtain the binder resin in a form suitable for the manufacture of friction elements. In all cases it is difficult to determine whether the phenolic resin and the metaborate react chemically with one another or whether they form a very intimate physical mixture; however, the products according to the invention do not appear heterogeneous and behave like homogeneous phenolic resins.

Suitable friction materials for use in composite friction elements made from the binder resin compositions according to the invention are substances known to Pich, such as, for example, asbestos. The compositions can furthermore be prepared by incorporating known filler materials ₃

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e.g. barite, metal chips, rubber, organic friction particles and graphite can also be modified Improvement of the hardening of the binder resin a methylene donor, such as hexamethylenetetramine, paraform or trioxane are present be.

The Relbungselemente can according to known methods for the bonding of the friction materials with the resins will. For example, the resin can be dry mixed with asbestos and the mixture under pressure under the Exposure to heat, or the asbestos can be molded using the wet mix dough process ("wet mix dough process") are impregnated with the solution of the resin, v / obei the solvent removed by drying prior to compression molding. A pressure of. at least 15.44 MN / m unü one Temperature of at least about 150 ° C used in the pressing process.

The invention is illustrated in more detail by the following examples.

example 1

a) Manufacture of butyl metaborate X! Tribut oxy bor ox ^^ - Zwischengn ^ "^ product

Equimolar amounts of orthofoic acid (9 »3 kg) and n-butanol (11.1 kg) were refluxed in toluene (9 kg) in a reaction vessel fitted with a stirrer and a Dean & Starlc water trap. After about 2 moles of water per mole of orthoboric acid had been released ₉ the mixture was under reduced! Pressure (10.6 KH / m) distilled to a final temperature of 160 ° 0 to remove the toluene su. Part of the product (13 kg) was used without further purification for the production of a boron-containing phenol-formaldehyde hardener.

turns.

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b) Production of a boron-containing Fhenolformiriäldehsdharzes

Phenol (400 g), 3? Ormaline (335 g, 36% by weight formaldehyde) and oxalic acid (2 g, dissolved in 4 g of water) were placed in a flask and heated to reflux with stirring. After refluxing for 2 hours 40 minutes, the mixture was heated under reduced pressure (10.6 KN / m 2) to a final temperature of 155 ° C. until a resin with a softening point (ring and ball) of 99 to 101 ⁰ C was obtained. The metaborate (60 g) from example a) above was added to the molten resin at 145 ° C. over 10 minutes, the mixture was stirred for 5 minutes and the product was then poured into cooling containers. Upon cooling the melt solidified and gave eir * clear yellow resin having a softening point of 91 ⁰ C (ring and ball) having a boron content of 1.3 $.

c) Application of the resin to brake linings

The resin (100 parts) according to Example b) was treated with hexamethylenetetramine (5 parts) ground and resulted in a powder with the following B.S. sieve analysis:

B.S. Sieve number

+ 60 '0.1 <fo

-60 +120 $ 1

-120 + $ 200 5>

Friction elements of the following composition were produced:

Asbestos 60 parts

Baryte 15 parts

Cellobond H 7534 Heibungspulverv2J 10 parts

ground resin / hexamine material as above

described, 15 parts

(all parts are parts by weight)

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The components were mixed, and the mixture in disk-shaped molded parts * ^ "long m pressed at 16O ⁰ C for 15 min with a pressure of 30.9 MN / The moldings obtained were post-cured using the following operations:.. The temperature was in 1 increased hour from ambient temperature to 150 ⁰ C, held for 2 hrs. at 150 ⁰ C, wit a Temperatürgradienten of tO ° C / hr. heated to 200 ⁰ C and then held. 16 hrs. at 200 ⁰ C.

The molded parts obtained were examined in an "inertia dynamometer" which simulated the conditions of a medium-sized sedan and was equipped with a disc brake . -Propertiesn ("friction / fade performances' *)

To determine the wear at low temperatures, at least 300 braking operations at 80 km / h. to zero "with a deceleration of 25 ° ß> g. The braking operations were carried out under constant torque conditions, and the temperature ran through the range of 80 ⁰ C to HO ⁰ Ci during each braking operation the decrease in weight and strength (" thickness ") were measured and graphically represented as a decrease per 100 braking processes ₀

The determination of the wear in the heat was carried out by braking processes at constant torque at a speed of 96.5 km / h to a standstill with a deceleration of 5% (1 braking process every 45 seconds); 15 braking processes were carried out in succession, the temperature rose during this time from the ambient temperature to 550 ° C. Three such series of tests were carried out and the average losses for 16 braking vox gears were shown in the drawing.

* "disc pads"

509819/1174 _SÄD original

Ver influence of temperature on the friction has been g by 25 consecutive Bremavorgänge at a delay of 50 56 96.5 xm / STDO (every 65 seconds 1 braking) examined "During this experiment, the temperature rose to 45O ⁰ Co

Results

1) wear cold wear heat wear

Standard Harness 0.35 g 0.076 mm 15.83 g 0.251 mm (unmodified)

modified resin 0.42 g 0.076 mm 15.36 g 0.289 of the example

2) friction

The results are in Pig. 1 included discussion of the results

The results of the wear test show that the inventive Resin performs similarly at both temperatures as the unmodified material "

Fig. 1) shows that the initial stabilization point of every braking process changes with increasing temperature. With the new material, the coefficient of friction never falls below the which was obtained during the first braking. With the unmodified However, there were eleven uses of the material in which the friction was lower than during the first braking process.

During each individual braking process was also in the course a change in the friction was detected during the braking process.

The friction members made from the resin of the present invention also showed an improvement in their maintenance Friction values for each individual braking process *

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The above results show that the invention Binder resins can be used to make friction elements that have good resistance to friction changes have with increasing temperature.

Example 2

Phenol (100 g), formalin (77.67 g, 36 wt .- #) 'and oxalic acid (0.53 g) in water (2.1 g) were placed in a reaction vessel equipped with a thermometer, stirrer and reflux condenser wax, submitted. The mixture was heated to a boil and held at reflux until it became cloudy. It was refluxed for a further 80 minutes. Then, after the resin was cooled slightly, a butadiene / acrylonitrile rubber latex (h0% solids, 14 g) was gradually added with stirring. The latex consisted of a commercial product, brand "Breon 1562 ^st .

The resin-latex mixture (10.6 * IOS / m) to a final temperature of 165 ° C distilled under reduced pressure and kept at this temperature until the Hovolakharz a softening point (ring and ball) of 95 - 105 ⁰ C had . Butyl metaborate (15 g, obtained according to Example 1) was added at atmospheric pressure over 10 minutes at 155 ° C and the mixture was stirred for 5 minutes. After pouring, the resin solidified and gave a material with a softening point of 93 ° G (Ring and ball).

Example 3

Phenol (2000 g), paraformaldehyde (540 g) and ammonia (0.91C / 400 g) were placed in a three-necked flask equipped with a thermometer, stirrer and reflux condenser, given. The mixture was gently heated to a boil and then held at reflux temperature for 60 minutes.

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The resole resin was distilled under reduced pressure (about 10.6 until it reached a temperature of 12O ⁰ C. Then the Butylmetaborat (300 g was obtained in Example 1) at Ätmosphärendruck during the fifth minute added "while butanol ( 75 let ml) abdestillieien. The resin was then poured out to yield a / solid having a softening point of 79 ° C (ring and ball) and a heat curing time of 5 minutes during cooling. at 130 ⁰ C.

Example 4

a) Preparation of the larger of the cyclohexyl metaborate

Equimolar amounts of orthoboric acid (155 g) and cyclohexanol (250 g) were refluxed in toluene (1 liter) for about 6 hours in a reaction vessel equipped with a Dean & Stark trap until about 2 moles of water per mole of orthoboric acid separated out and the solution became clear. About 300 ml of toluene was distilled off and the solution allowed to cool. The cyclohexyl metaborate crystallized and was filtered off _o The crystals a few hours in a vacuum oven at 100 ⁰ C were then dried.

fr) Production of a boron-containing phenol-formaldehyde resin a

Phenol (1,100 g), formalin (36 wt .- ^, 880 g) and oxalic acid (7.7 g) in water (11 g) were placed in a flask fitted with a thermometer, stirrer and reflux condenser. The mixture was heated to a boil and held at reflux temperature until it became cloudy. Then it became more Held at reflux temperature for 100 min. After that, that became

Resin under reduced pressure (10.6 KH / m) to a final temperature of 150 ⁰ C distilled

The cyclohexyl metaborate (87 »5 g, prepared as above) was added to 500 g of melted Novclak and the mixture 10 children long at 145 - 150 ° 0. She was then assumed

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poured and solidified on cooling, whereby they a clear result.

clear yellow resin with a softening point of 104 ° C

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Claims (1)

Claims 1. A binder resin for the production of Reiburigaelementen, characterized in that it comprises a phenolic resin, reacted with or containing a metaborate of the empirical formula ROBO, wherein R is an alkyl, alkenyl, cycloalkyl or aryl hydrocarbon group, in an amount , for a borrowed content of _t about 0.5 to 3 »0 wt .- ^, based on the total binder resin Binding resin according to claim 1), characterized in that the phenolic resin is made from phenol and formaldehyde. . 3. Binder resin according to claim 1) or 2), characterized in that the R is a lower alkyl group having about 1-6 carbon atoms means. 4ο binder resin according to claims 1) to 5), characterized ,, that the boron content is about 1.0 to 2.0 wt .- #, based on the entire binder resin. 5, friction element, characterized in that it can be Binder resin according to claims 1-4. 509819/1174 / IH Blank page