CA1075843A

CA1075843A - Resin coated glass fibers and method of producing same

Info

Publication number: CA1075843A
Application number: CA231,920A
Authority: CA
Inventors: Carl A. Johnson
Original assignee: Owens Corning Fiberglas Corp
Current assignee: Owens Corning
Priority date: 1974-09-20
Filing date: 1975-07-21
Publication date: 1980-04-15
Also published as: US4039716A; JPS5149991A; GB1503926A; BE833356A; FI59381C; IT1042713B; FI752475A; FR2285352B1; AU8372275A; FI59381B; DE2534760A1; FR2285352A1; DK421275A; NL7511056A

Abstract

ABSTRACT OF THE DISCLOSURE
Glass fibers are coated with a size comprising emul-sified particles of a prepolymer having an organo function non-ionic hydrolyzable silane locked into the protective colloid layer surrounding the particles. The silane coated prepolymer particles have an overlay of an ethoxylated fatty material. The size also contains a lubricant comprising emulsified particles of a lubricant oil emulsified with a mixture of ethoxylated fatty alcohols, ethoxylated fatty acids, and a diethoxylated fatty amine. The water phase of the size involves a dissolved cationic silane, as for example, gamma aminopropyltriethoxy-silane and dissolved nonionic lubricant, as for example, an ethoxylated fatty acid. The preferred emulsifier for the pre-polymer is a polypropylenepolyethylene adduct. The size is made by adding an organo functional nonionic hydroy? sil-ane monomer to the emulsion of the prepolymer so that the silane adds to the oil phase. Thereafter the water solution of the silane and the water soluble lubricant are added, followed by the emulsion of the oil.

Description

~o~s~

The invention relates generally to a size for glass fibers and also ~o glass fibers coated in accor-dance with the size of the present invention. A method of incorporatlng a silane coupling agent into an aqueous mixture for application to glass fibers is also embodied in the present lnvention.
In the art of producing glass fibers as a rein-forcement for thermoplastic and~or thermosetting resins it has long been known to coat the fibers with an organ-ic polymer before embedding the coated fibers in the laminating resin. The fibers are most economically coat-ed with the polymers at forming. Because the fibers are formed immediately beneath red hot bushings having orifices therein through which the molten glass passes before solidifying into the fibers, the solidified fib-ers are best coated with an aqueous emulsion of the polymer in order to avoid a fire hazard. Numerous pro-blems exist in the pxocess of applying a prepolymer to the glass fibers from a water phase. One problem is that the size that is used to coat the fibers contains a high percentage of water which causes migration of the size solids during dr~ing of the coiled packages of the coated fibers. Additional water also requires additional drying, which when accomplished by a gas-fired oven produces additional discoloration of cat-ionic materials in the glass. In addition, the sil-anes which are added to the size slowly hydrolyze on - standing, and in doing so agglomerate. The emulsified particles of the prepol~mer may also slowly agglomer-ate on standing, and the coating on the fibers of the :
.
' ' :

i~751~91t3 ag~lome~ated material usually leaves some areas of the fibers devoid of a coating. When incompletely coated fibers are used as a reinforcement ~or lamina-ting resin, a poor bond of the lamina-ting resin to the fibers results in certain areas and these areas then break down under repeated reversals of stress.
It is deslrable to produce coated fibers for use as a reinforcement for thel~oplastic and/or thermosetting laminating resins and which coated fibers are more uniform~y coated and have a thicker coating than has been provided heretofore with simi;-lar materials. It is further desirable to produce sizes of high prepolymer concentrations which are more stable over a greater length of time than are prior art sizes made of the same prepol~mers. It is also desirable to produce sizes which mose adequately lubricate the fibers in a wet condition so that fewer of the fibers become abraided prior to the time that the wetted fibers are dried and the coating of the prepolymer produced. It is further desirable to pro-duce an emulsion of a lubricant which more adequately protects the fibers from abrasion while the water is present and which at the same time does not inter-fere with the wetting out of the surface of the glass fibers by the prepolymer during the drying operation.
~ .
It is further desirable to provide a cationic lubri~
cant containing nitrogen which does not discolor when dried in a gas~fired oven.
.:

~` 30 , 2 -~13 ~' ~

... .
.

3~075843 ~ ccor~lincJ to the present invention there is providecl a siz~ Eor co~tinc; a ~Jlass Eiber to facilitate admixture thereof with a resin, the size including an ~queous emulsion comprising an oleophilic prepolymer, an ethoxylated nonionic emulsifying agent, a nonionic hydrolysable silane and an ethoxylated fatty material to inhibit hydrolysis of the silane.
According to a further aspect of the present inven-tion there is provided in a size for coating fiber ylass a method of inhibiting hydrolysis of nonionic hydrolysable silanes which are incorporated in an aqueous emulsion of an oleophilic prepolymer emulsified by an ethoxylated nonionic emulsifying agent, the method including the step of introducing into the size an ethoxylated fatty material.
The invention in general describes a size - suitable for coating glass fibers used in reinforcing resin molded products. The size enhances bonding between the glass fibers and the resin. The size is aqueous based to reduce the fire hazard caused by con-tact with the hot newly formed glass fibers. However, the size does not contain excess water so that long drying periods are not necessary. This avoids dis-~ coloration of the glass fiber. Further the size particles -~ do not migrate so that uniformity of bond strength between the glass fibers and the resin is enhanced.
The size described herein prevents the hydrolysis and agglomeration of the silane and emulsified prepolymer with the passage of time. Hence the size can be stor-}

~....... ' "'"',' ~ ~ , ~, ~

ed before use without detriment.
According to one embodiment of the invention ` the size may be produced as follows:-An aqueous emulsified prepolymer is prepar-ed by mixing the prepol~mer, which can be any oleophi-lic polymer, and an emulsifying agent which can be any ethoxylated nonionic emulsifying agent. Preferably the emulsifying agent ~ill be an adduct of polyoxyethylene and polyoxypropylene.
A nonionlc hydrolysablesilane isadded tothe emulsified pre~olymer. An emulsifiedlubricant oilis added to theemulsified prepolymer. The lubricantoil isemulsified with ethoxylated fatty materialswhlch alsoact toprevent hydrolysis ofthe nonionichydrol~sable silane.
A cationic hydrolysable silane is added to the aqueous phase. This cationic silane reacts with the glass flber rapidly at the start o~ the prepara-~ tion and ensures glass receptivit~ to the emulsified ; prepolymer~nonionic silane mixtuxe. Additional com-mercial emulsifying agents and pH control agents may be used.
Obviously, a coating material which pro~
vides the above desirable properties will provide a ~ -material that is a considerable improvement over the prior art. Particulars of such materlal will now be given in the following ex~mples.
EX~MPLE l A size was made of the followlng materials given in parts b~ weight.

r 4 r :
y ~-,-''' . ' ! , 1~3758~3 ~aterials P ts b~ Wt.

Emulsion of the reaction product 66.22 of bisphenol A and epichlorohydrin having an average epoxy equivalent weight of 240 stabilized with an adduct of polypropylene oxide and polyethylene oxide having a molecular weight of 400 (56~ solids) Lubricant: 30% white oil, 3.76 10 30~ ethoxylated fatty acid, 30~ Pthoxylated myristyl alcohol, 10~ diethoxylated fatty amine Polyethylene glycol 400 15.36 monostearate Acetic acid 3.01 Gamma-methacryloxypropyltrimethoxysilane 1~.03 Gamma-aminopropyltrimethoxysilane 3.76 Deionized water 728.87 In the above lubricant, the ethoxylated fatty alcohol is C14H29O(C2H4O)nC2H5OH, the ethoxylated fatty acid is CH3(CH2)7-CO(C2H4O)nC2H5OH, and the diethoxylated fatty amine ~ C2H4o(c2H4o) H
is RCH2N x ; wherein R is a mixture of fatty ~ C2H40 (C2H4) x alkyl radicals of from C4 to C18 inclusive; n is a number to provide an average molecular weight of 400 and x is a number to provide an average molecular weight of 200.
The size was prepared by adding 8 parts of deionized water to a mixing kettle followed by the emulsion of the prepolymer. Thereafter the methacryloxypropyltrimethoxysilane was added and mixed for 5 minutes,following which 160 parts of ; 30 water were added and mixed for 15 minutes. This proauces an emulsion of prepolymer and silane.
In another mixing kettle 8Q parts of deionized water were added and the gamma-aminopropyltrimethoxysilane was added thereto with mixing. Thereafter the acetic acid was added and mixed, and the mixture was then added to the previously mixed ~ 3 11:37~8~3 prepolymer and silane emulslon. In a third kettle the polyethy-lene glycol 400monostearate, and the mixtureof white oil, ethoxy-lated alcohol,ethoxylated ~atty acid weremixed anddiethoxylated fatty amine mel~edtherewith. Waterat 140Fwas addedwith mixing to producean emulsion. Thereafter an additional80 parts o~deio-nized waterwas added withmixing, andthe mixtureobtained wasthen added to the emulsion of the prepolymer. The size was stable over a period of at least 72 hours.
The size was applied to 2080 E-glass fibers using a roll-type applicator, following which the fibers were grouped together into a strand and the strand was wrapped upon a revolving mandrel to produce a package. The strand had very good forming properties with no Euzz. The 45-pound package was placed in an oven heated to 2350F, and was dried for 42 hours. Four strands were grouped together to form a bundle that was used to produce filament wound pipe by passing the strands through a resin bath comprising a solution containing 100 parts by weight of Dow Chemical Co. DER 331 epoxy resin and 14 parts by weight of meta phenylenediamine curing agent and thereafter bringing the coated strands together to form the bundle. The resin has the following formula:

r CH3 H O H CH3 H O
H-C-C-C- -O- ~ C- ~ O-C-C-C- -O- ~ C- ~ O-C-C-C-H

The coated strand was pulled through the guide eyes o the filament winding apparatus and was then wound upon a mandrel at a helix angle of 54 3/4 to provide a pipe having an inside diameter of 2.235 inches and a wall thickness of 0.075 inches. The resulting filament wound material was cured at 275F~

.

*Trademark - 6 -~' .

~0~5843 for one hour. The pipe had a fiber loading of 66% and whentested according to ASTM Spec. D-2143 withstood 4,000 pressure cycles between 0 and 1100 psi before electrical conductivity was established through the pipe.
The weeping of filament wound pipe is believed attributed to a fatigue failure between the laminating resin and the glass fiber reinforcement resulting in fatigue cracks in the now unreinforced laminating resin. In order to get an improvement in this cycle to weep test, therefore, either a stronger bond must be produced between the laminating resin ~- and the glass fiber reinforcement, or a reduction in the number of broken glass filaments must be provided in the roving. It is believed that the size of the present invention more adequately lubricates the fibers against abrasion while passing over guide surfaces both in the wet condition and in the dry condition to reduce the number of broken filaments; and in addition, produces a better bond between the glass fihers and ;~
the coating produced thereon.
As previously indicated, the above described strand processed very well and produced substantially no fuzz. The assignee of the present invention has an "abrasion gate"
machine for evaluating the amount of fuzz produced by fibers. ~-~
The abrasion gate machine comprises intermeshing top and bottom frames of horizontal rods. The bottom frame is stationary and comprises eleven 3/16" diameter chrome plated steel pins. The upper frame has 10 similar pins similarly spaced and arranged so that its pins fit into the spaces between the rods of the bottom frame. All of the pins have a 10 microinch finish. The abrasion gate is mounted in a box having a false bo~tom made of 50 x S0 mesh wire screen. Suction is applied to the bottom : E~
-~
.
:--,- . . . ......................... .
. .- ` .

~75~3~3 beneath the screen to c~use an air flow over the rods to pull fuzz generated on the rods down onto the screen. The strand to be tested is strung between the upper and lower frames, and the upper frame is forced down onto the lower frame with a force of 0.30 pound. After 400 yards of strand are pulled through the apparatus, the fuzz collected on the screen is weighed, and the tension re~uired to pull the strand through the gate is measured. The dry strand produced as above described when pulled through the Finger Gate apparatus required a tension of 330 grams, and no fuzz was collected.
By way of contrast, and not according to the invention, the Pittsburgh Plate Glass Co. strand 1064 NT 9 required a tension of 355 grams, and 9 samples gave a minimum amount of fuzz of 7.9 milligrams and a maximum amount of 9.6 milligrams per salllple.
EX~MPLE 2 The process of Example 1 was repeated excepting that the strand was pulled through a bath of Dow Chemical Co.
; Derakane 411-45 polyvinyl ester resin, instead of the epoxy ; 20 resin of Example 1. The filament wound pipe required 3,156 cycles to weep when stressed between 0 and 1150 psi.
By way of contrast, a pipe prepared similarly excepting that the fibers used were the commercially available -` Pittsburgh Plate Glass Co. 1064 fibers withstands only 1,302 pressure cycles.
In a further test, Naval Ordinance Laboratory test rings were made according to ASTM SpecO D-2291 using the strand of Example 1 and the Derakane resin 411-45, and were tested according to ASTM Spec. D-2344-72. The test ring had a resin 30 content of 18.796, and had a tensile strength of 8,460 psi dry.

*Trademark , .

~7~843 After boiling for 24 houxs ~n water at atmospheric pressure the rinas had a streng-th of ~,l90 psi, By wayof contr~st,and notaccording tothe invention, the Pittsburgh PlateGlass Co.strand 106~NT 15when similarlytested had a dry strength of8,080 psi,and after24 hoursof bollinghad astrength of 7,730psi. The ringshad a resin content of 21.6~.

The processof Example 2is repeatedexcepting thatan emul-sion ofa polyesterresin isused forthe coatingof theglass in place of theemulsion ofthe epoxymaterials. The polyesteris madeby cook-ing lmole ofortho-phthalic anhydride, 1 mole of succinic anhydride, and 2.4moles of propylene glycol toan acid value of 30 to 35. An emulsion is made thereof from the following materials:
Materials % By Wt.
Above polyester prepolymer 47.5 Xylene 5.3 Diacetone alcohol 10.6 Wyandotte Chemical Co.
Pluronic* LlOl emulsifier 2.6 Wyandotte Chemical Co.
20 Pluronic* P105 emulsifier 7.6 ~ater 26.2 Pluronic L101 and P105 are both block copolymers of propylene oxide andethylene oxider L101 beinga relativelylow molecularweight liquid andPl05 beinga relati-~ely highmolecular weight paste.
The emulsion is made by thinning the polyester with the xylene. In another ~essel the emulsifying agents are diluted with the diacetone alcohol, and thereafer the diacetone alcohol solution of the Pluronics is added to the polyester solution with agitation until a homogeneous mixture is produced.

Thereafter the water is slowly added to the main mix with agitation until the lnversion point is reached, following which ., _g_ *Trademark 1~:)758~3 the balance ofthe wateris slowlyadded withagi-tation toproduce a stableemulsion. Therea~terthe processof Examplel iscontinued.
The coatedstrand producedusing th:is polyester film former pro-cesses substantially as well as the epoxy sizeof Example2 dur-ing the wet ancl dry conditions and gives ~ubstantially no fuzz when pulled through the abrasion gate apparatus.
EX~MPLE 4 The process of Example 3 is repeated excepting that Wyandotte Chemical Company X-1042 polyurethane latex (50% solids) is substituted for the emulsified polyester of Example 3. The coated strand so produced processes as well during the wet and dry stages as do the materials of Examples 2 and 3, and produces no fuzz when pulled through the abrasion gate apparatus.
EX~MPLE 5 The process of Example 1 is repeated excepting that gamma-glycidoxypropyltrimethoxysilane is substituted for the gamma-methacryloxypropyltrimethoxysilane. This material processes as well during the wet and dry stages, and gives ~` substantially the same strength as do the materials of Example 1.

The process of Example 1 is repeated excepting that beta-mercaptoethyltrimethoxysilane is substituted for the gamma-methacryloxypropyltrimethoxysilane. The strand so produced processes as well during the wet and dry stages, and has substantially the same strength as do the materials of Example 1. .
: EX~iPLE 7 The process of Example 1 is repeated excepting that polyethylene glycol 4~0 monooleate is substituted for the polyethylene glycol 400 monos~earate, and the strand so produced ., , ~75~34~

has substantially the same properties as do those of Example 1.

The process of Example 1 is repeated excepting that corn oil is substituted for the white oil of the lubricant given in Example 1, and the strands so produced has substantially the same properties as do those of Example 1.

The process of Example 1 is repeated excepting that polyoxyethylene palmitate is used as the emulsifier instead of the adduct of polypropylene oxide ~nd polyethylene oxide of Example 1. The strands so produced has substantially the same strength and low fuzz as do those of Example 1.

The process of Example 7 is repeated excepting that n-beta(aminoethyl) gamma-aminopropyltrimethoxysilane is used in place of the gamma-aminopropyltrimethoxysilane. The strand so produced has substantially the same properties as does the strand of Example 1.
It is believed that the present invention pro-vides an improvement over the prior art in the followingrespects:
1. An organo functional silane monomer is added to the emulsion of the coating prepolymer without hydrolyzing the silane prior to its addition, so that the silane becomes part of the oil phase and is taken up in the emulsifying agent on the surface of the prepolymer particles. Inthis locationthe - silane monomerprobably orlentswith thesilicone groups adjacent the prepolymer with the long organo radical projecting out of the surface. A polyoxypropylene-polyoxyethylene adduct is a preferred emulsifier of the prepolymer for reasons which will :, ~;
. ,~-- , . , ~7S!3~3 later be apparent. Immecliately after the addition of the silane to the emulsion oE the prepolymer, a water solution of an e-thoxylated fatty al~yl radical is added, and this material overcoats the silane in the surfactant layer to temporarily lock up or encase the silane on the surface of the prepolymer particles. By this mechanism the rate of hydrolysis of the silane is reduced and greater emulsion stability i5 achieved at high mix solids.

2. In addition to using a silane which is locked up in the emulsifier of the prepolymer, a dissolved cationic silane monomer may be used in the aqueous layer. The dissolved silane is available immediately to adhere to the glass on contact of the water therewith to provide protection for the glass immediately after the initial contact. The dissolved silane is beneficial even though -the silane has no functionality for bonding with the laminating resin.

3. Further protection for the glass fibers in the wetted condition is provided by an ethoxylated fatty radical dissolved in the water layer.

4. An improved emulsified lubricant is provided which moves to the surface of the glass in an emulsified condition while the fibers are wet with water, and which later moves away from the surface of the glass during drying to permit the prepolymer having the silane locked into its surface to better wet out the surface of the glass fibers. This flip-flop of the emulsified particles of oil is accomplished by using surfactants, all of which are ethoxylated, and one of which is a diethoxylated .~ alkyl amine. This amine is cationic in a water layer, and loses ` its cationicity when dried. The amine further is loosely bound to the remainder of the emulsifying materials by secondary ''Ei~

. ~

7S~143 forces, inasmuch as they all have long ethoxylated chains oriented outwardly of the surface of the particles. Upon drying the emulsion is believed to invert from an aqueous emulsion to an oil emulsion, and the ethoxylated chains join together into a nucleus with their oily tails on the surface. When this occurs, they move away from the surface of the glass and make way for the prepolymer particles. Further advantages are had by using a soluble lubricant in the oil phase which also has an ethoxylated chain.
The above improvements can be used either singly or in combination with each other to obtain desired results.
It will now be apparent that the prepolymer for the coating material can be any oleophilic polymer, either thermo-plastic or thermosetting, and will include polyesters, alkyds, polyurethanes, polypropylene, polyethylene, amides such as nylon, acetyl resins, formaldehyde condensates, phenol-formal-dehyde condensates, elastomers such as polybutadiene, butadiene-styrene, butadiene-acrylonitrile, vinyl polymers such as poly-vinyl chloride, polyvinyl acetate, the methacrylates, tetra-fluoroethylene, etc.
The organo functional silane which is added to the oil ~ phase can be any oleophilic silane, such as carboxyphenylsilane, i allylsilane, vinylsilane, vinyltriethoxysilane, vinyl-tris (beta methoxyethoxy) silane, gamma-glycidoxypropyltrimethoxysilane, beta-(3,4 epoxycyclohexyl)-e~hyltrimethoxysilane, etc.
The prepolymer may be emulsified using any nonionic emulsifying agent, but the preferred emulsifying agents are adducts of polyoxypropylene and poly~xyethylene. The emulsifylng agent which are dissolved into the water phase and which are used to cover the silane on the prepolymer particles can be any ethoxylated fatty matexi~lsuch asa fatty ~.:i ; ............ . : , ,'i ~ ~ '' '' : ' " .'.. ';' ' ' .

7~8~;~

ether or ester of a polyoxyethylene or polyglycol; and the cationic silane that is dissolved in the water phase for the immediate coatiny of the glass fibers, can be any nitrogen containing silane, as for example, the gamma-aminosilanes, N(B-aminoethyl) gamma-aminopropyltrimethoxysilane, normal-phenyl-gamma-aminopropyltrimethoxysilane, m-aminophenyl-triptychsiloxazolidine, normal-beta-(aminoethyl) gamma-amino-propyltrimethoxysilane, etc.
The fugitive cationic lubricant which is attracted to the glass in the wet condition and which moves away from the glass while drying can be made from any oil, either saturated or unsaturated, but is preferably saturated where changes in color, etc. are not wanted. A saturated petroleum white oil is such a preferredmaterial. Theoil isemulsified usingethoxylated fatty materials,such asfatty alkylmaterials ormaterials contain-ing fattyalkyl radicals,such asthe radicalsof fatty alcohols,or fatty acids, or the comparable alkyl chain devoid of the ether or ester linkages. Such can be made for example by reacting a fatty acid with amines to form a nitrile followed by the removal of water from the nitrile, followed by hydrogenation to produce the primary amine of the fatty material. A mixture of chain lengths of the fatty materials is preferable and this is easily accomplished by using a mixture of ethoxylated fatty alcohols, and ethoxylated fatty acids. Such materials are then made cationic by mixing with diethoxylated amines which ; also contain such a fatty alkyl radical. Preferred materials contain 20% to 75% of an ethoxylated fatty alcohol, 20~ to 75%
of an ethoxylated fatty acid, and 5~ to 60% of an ethoxylated fatty amine.
Preferred size compositions will comprise the following materials in percent by weight of solids:

, . ~
.

1~7S8~;~

Materi~ls~ By Weight Preferred Emulsion prepolymer solids 33 - 6~ 46.5 stabilized by an adduct of polyoxypropylene and polyoxyethylene Emulsified solids of an 3 - 10 5 oil stabilized by an ethoxylated fatty amine Polyethylene glycol of a 10 - 35 21 10 fatty radical Nonionic trialkoxysilane 5 - 25 19 Cationic trialkoxysilane 1 - 15 5.5 Acetic acid 0 - 5 3 The size as applied to the fibers may contain from 2% to 20~ solids, and ideally approximately 9% to 10% solids.
It will now be seen that in the most preferred size arrangement, all of the surfactants that are used have a common denominator in that they include ethoxylated chains. By doing so, all of the surfactants can group together in the drying phase as the emulsion inverts into an innocuous material coated with fatty radicals which cause such particles to then become lubricants - which are generally nonionic, and which will move away from the glass. After drying, it then coats the surface of the polymer coating that is formed on the glass. Even in this position, such materials are innocuous when the polymer coated fibers are immersed in the laminating resin, since they again can move into the laminating matrix and become compatible therewith.
It will now be seen that the present invention has combined a number of advancements in the art, one or more of which can be used separately, but which ideally combine with each other to produce compatibility not achieved heretofore.

The locking up of a silane in the surfactant layer of the prepolymer to prevent its hydrolysis and polymerization is, to ~ 15 ~

~7 , :~ .

1~3758'~3 the writer's knowledc~e, novel and will contribute stability-to any oleophilic silane used in any size. The inclusion of etho~ylated fatty material over the top of the silane, likewise can be used in any size composition where silanes are used.
The preparation and use of a cationic lubricant wherein the cationicity is imparted by the surfactant and not the oil itself and wherein each of its surfactants contain ethylene oxide chains can also be used with benefit in other size formulations with or without the other improved size materials previously referred to. The specific combination of all of the materials, however, has benefits wherein the surfactants invert and combine during the drying stage into innocuous materials which leave the vicinity of the glass. In those instances where acetic acid is - specified in a size, it will be understood that it is used for pH adjustment only, that other acids can be used, and that it is not an essential part of the size coating.
` While the invention has been described in considerable detail, I do not wish to be limited to the particular embodiments shown and described, and it is my intention to cover hereby all novel adaptations, modifications, and arrange-ments thereof which come within the practice of those skilled in the art and which fall within the purview of the following claims.

` ' . .
.'.`

.:

~ 16 ~
~3 . .
., .

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A size for coating a glass fiber to facilitate admixture thereof with a resin, said size including an aqueous emulsion comprising an oleophilic prepolymer, an ethoxylated nonionic emulsifying agent, a nonionic hydrolysable silane and an ethoxylated fatty material to inhibit hydrolysis of said silane.

2. A size according to claim 1,further comprising a lubricant to provide a surface lubricant for a coated glass fiber.

3. A size according to claim 2, wherein said hydroly-sis inhibiting ethoxylated fatty material also emulsifies said lubricant.

4. A size according to claim 1, 2 or 3, further com-prising a cationic hydrolysable silane to enhance the receptivity of the glass fibers for the nonionic hydrolysable silane.

5. A size according to claim 1, 2 or 3, wherein the prepolymer is any thermoplastic or thermosetting oleophilic polymer.

6. A size according to claim 1, 2 or 3, wherein the ethoxylated nonionic emulsifying agent is selected from the group comprising an adduct of polyoxyethylene and polyoxypropylene and polyoxyethylene palmitate.

7. A size according to claim 1, 2 or 3, wherein the nonionic hydrolysable silane is a trialkoxysilane.

8. A size according to claim 1, 2 or 3, wherein the hydrolysis inhibiting ethoxylated fatty materials are selected from the group comprising ethoxylated fatty acids, ethoxylated fatty alcohols and ethoxylated fatty amines.

9. A size according to claim 1, 2 or 3, further com-prising a pH controlling agent.

10. A size according to claim 2 or 3, wherein the lubricant is selected from the group comprising white oil and corn oil.

11. A size according to claim 1, having the following composition:
% By Weight Emulsion prepolymer solids stabilized by an ethoxylated nonionic emulsifying agent 33-66 Emulsion solids of a lubricant stabilized by an ethoxylated fatty material 3-10 Polyethylene glycol fatty radical adduct 10-35 Nonionic trialkoxysilane 5-25 Cationic trialkoxysilane 1-15

12. A size according to claim 11, wherein the pre-polymer is a diepoxide of bisphenol A.

13. A size according to claim 11, wherein said non-ionic trialkoxysilane is selected from the group comprising gamma-methacryloxy-propyltrimethoxysilane, gamma-glycidoxy-propyltrimethoxysilane and beta-mercapto-ethyltrimethoxysilane and said cationic trialkoxysilane is selected from the group comprising gamma-aminopropyl-trimethoxysilane and n-beta (aminoethyl) gamma-aminopropyltrimethoxysilane,

14. A size according to claim 11, 12 or 13, wherein said emulsion solids of a lubricant comprises 20 to 40% of ethoxylated fatty acids, from 20 to 40% of ethoxylated fatty alcohols, from 5 to 15% of diethoxylated fatty amines, and the balance being lubricant.

15. A size according to claim 1, having the following composition:

% By Weight Emulsion prepolymer solids stabilized by an ethoxylated nonionic emulsify-ing agent 46.5 Emulsion solids of a lubricant stabilized by an ethoxylated fatty material 5 Polyethylene glycol fatty radical adduct 21 Nonionic trialkoxysilane 19 Cationic trialkoxysilane 5.5 Acetic acid 3

16. A glass fiber coated with a size according to claim 1, 2 or 3.

17. A glass fiber coated with a size according to claim 11, 12 or 13.

18. A glass fiber coated with a size according to claim 15.

19. In a size for coating fiber glass a method of inhibiting hydrolysis of nonionic hydrolysable silanes which are incorporated in an aqueous emulsion of an oleophilic prepolymer emulsified by an ethoxylated nonionic emulsifying agent, said method including the step of introducing into said size an ethoxylated fatty material.

20. The method according to claim 19 including the steps of firstly emulsifying said prepolymers secondly adding said nonionic hydrolysable silane and thirdly adding said ethoxylated fatty material.

21. The method according to claim 19 including the step of adding a cationic hydrolysable silane to the aqueous emulsion to enhance the receptivity of the glass fibers for the nonionic hydrolysable silane.

22. The method according to claim 19, 20 or 21 wherein a lubricant is added to the aqueous emulsion and said ethoxylated fatty material acts as an emulsifying agent for said lubricant.