CA1089138A - Sizing glass fibers for thermoplastic resin reinforcementt - Google Patents

Abstract

Abstract Glass fibers for reinforcing thermoplastic resins are sized with an aqueous dispersion comprising a poly-urethane-ionomer as a film-forming agent and a bonding agent comprising an expoxy-containing alkoxysilane. Advantageously the polyurethane is a very small particle ionomer and the bonding agent is selected from the group consisting of (a) an epoxyalkyl alkoxysilane + an aminoalkyl alkoxysilane, (b) an epoxyalkyl alkoxysilane + a low-molecular weight aliphatic primary or secondary mono-amine, (c) an aminoalkyl alkoxysilane + a low-molecular weight monoepoxide, and (d) an epoxyalkyl alkoxysilane.

Description

This invention relates to a process for producing glass fibers for the reinforcement of thermoplastic resins such as polyamides, polycarbonate~ or polyesters.
It is known that glass fibers, preferably in the form of cut strands composed of bundles of endless fibers joined together, can be used for reinforcing thermoplastic resins In order to obtain effective reinforcement in the polymer matrix, it is necessary to ensure that the glass fib~r strands do not lose their coherence before they are incorporated in the polymer and that the coating ~
composition which bonds the glass threads together est- ~ -ablishes a firm bond between the polymer matrix and the glass iibers without any deleterious chemical reactions occurring between the polymer matrix and the coating comp-osition which could lead to undesirable diæcoloration and partinl degradation of the polymer.
The coating composition is normally produced on the glass iib rs as follows. As soon as the glass fibers, which are extruded from the bushlng at high velocity, have solidified, that iæ to say even before they are spooled, theg are sized by means oi a suitable apparatuæ (rollers or spray device), i.e. they are impregnated with an aqueous mixture which normally consists of at least one iilm-forming agent and a bonding agent, in addition to other additives, and which is known as "size", and they are then dried at temperatureæ above 100C. The process of drying includes not only the removal of water or other volatile constituents (solvents) but also the hardening oi the size components, in particular of the film-iorming agent.
Le A lS 770 - 2 -lt is only when drying has been completed that the size has become a solid coating compound. This coating compound serves to ensure problem-frec processing of tl~e glass fiber strandæ during rewinding and/or cutting.
1~ thc glass fiber strands are made up into chopped strands in a conventional manner, it is most important that this chopped product should have a high bulk density in order to minimize the volume of space required for collec-tion and shipment, in the interest of economy.
It is equally important to be able to empty the chopped strands rapidly and without obstruction from their containers, which are sometimes very large, and convey them through suitable dosing devices (vibrating chutes or the like) to an extruder where they are mixed with the polymers which are to be reinforced, In order to impart to the continuous or chopped glass fiber strands the necessary properties to ensure this, such as coherence Or the individual strands, freedom from lumps and pour-ability, it is essential to dress the strands with a coating compound, i.e. to size them. Apart from the functions already mentioned, it is an important function of the size or of the coating compound produced from it to ensure that the mechanical properties imparted to the glass fiber-reinforced polymers by the reinforcement with slzed glass fibers is substantially maintained even under the action of water in the form Or atmospheric moisture or after storage in cold, hot or even boiling water.

Le A 15 770 _ ~ _ - - . . . . . ~ ... ..

108gl3~

The numerous require~ents which must be met by glass fi~ers, pnrticularly if they are to be used aschopp~d strand~
for the reinfor~ement of polymers, have not to this day been able to be fulfilled satisfactorily.
In German Offen~egung~schriften No. 1,922,441 and No. 2,300,36~, it is recommended to use nonionic, hardenable ~artially or comp]etely blocked polyurethanes as film-forming agcnts in si~s for glass fibers which are used for rein-forcing polyamides. In the processes described in these Offenlegungs~chriften, commercial silane bonding agents such as r -aminopropyl triethoxysilane, ~ -glycidoxypropyl-trimethoxy silane, ~-(3,4-epoxycyclohexyl)-ethyl trimeth-oxysilane or N-(~-aminoethyl)- ~-aminopropyl-trimethoxy-silane are used in addition as bonding agents. The rein-forcing éffects which can be achieved with such sizes are not satisfactory, in particular with regard to the import~nt ~echanical properties o~ glass f~ber -reinforced polyamides, such as their flexural strength, impact strength and notched impact strength.
It is also known that unsized (so-called water-sized) glass fiber~ only insu~ficiently lmprove the mechanical properties oi thermoplastic resins, e.g. their impact strength. For this reason, and also to ensure satisf~ctory handling and processing, e.g. rewlnding or cutting by con- ;~
ventional methods, it is customary to treat glass fibers which are intended for reinforcing thermoplastic and hardenable polymers, including also thermoplastic poly-esters, with a size, thereby producing a solid coating on the glass iibers. This coating is intended to protect Le A lS 77 ;

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the glass fibers against mechanical damage, to ensure that th~ numerou~ individual threads of which the glass fibers strands are co~posed will hold together during the operations carried out on the ~trands between their manufacture by a conventional mechanical drawing process and their incor-poration in the polymers which they are intended to rein-force, and above all to establish between the glass-fiber~
and the polymer a true bond which will substantially with-stand the action of water. By a true bond is meant a firm adherence between the two components of the glass fiber/
polymer compound material, which is the necessary pre-condition for an optimum reinforcing effect of the glass ri bers.
It is therefore of major technical importance to develop suitable sizes for glass fibers, in particular for the known A-, C- and E-glass fibers, 90 that these fibers will come as close as poæsible to producing the maximum reinforclng effect theoretically obtainable in polymers.
By sizes for glass fibers are meant aqueous mixtures which contain as their major constituents a film-forming aglent and a bonding agent.
The film-forming agent used is generally an emul-sifiable or dispersible organic polymer. The bonding agent is normally a silane bonding agent or a chromium B complex compound, e.6. the product "Volan A" (Manufacturers:
- Du Pont, USA). In addition, the sizes frequently contain lubricants, antistatic agents, emulsifiers and other additives.
Le A 15 770 - 5 -f, ~

108~13~ -~
The sized glass-fibers which have been developed to a high degree of perfection for reinforcing unsaturated polyester resins, so-called UP-resins, are less suitable for thermoplastic polyesters. The additives (epoxysilanes) specifically recommended for improving the mechanical properties of glass fiber-reinforced thermoplastic polyesters (see German OS No. 2,206,804) are also only partially satisfactory since it is not possible to achieve with the aid of these additives the optimum values of important mechanical properties such as the notched strength and the flex-ural strength.
It is therefore an object of this invention to developglass fibers having surface finishes which are particularly suit-able, for reinforcing thermoplastic resins. In particular, it ;
is intended to improve the flexural strength and notched impact strength of composite materials to glass fibers and thermoplastic polymers.
This invention therefore relates to an aqueous disper-sion suitable for use as a sizing composition for glass fibers ;~
comprising a polyurethane ionomer as a film-forming agent in a concentration of about 1 to 15% by weight, said polyurethane ionomer being characterized by (a) having an average particle size of about 0.05 to 0.5 ~
(b) having an ionic group content of about 5 to 30 milliequivalents per 100 g, and (c) being capable of forming a film when dried which has a tensile strength of at least about 50 kp/cm2, an elonga~
, tion at break of about 100-600%, a Shore-A-hardness of about 50-90? a swelling in water of less than about 30%, and being ~`

insoluble in 80% aqueous tetrahydrofuran after heating to 140 C, the dispersion further comprising from about 0.05 to 1.5% by -- -weight of an epoxy-containing bonding agent, selected from the ~ ;
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group consisting of (a) an epoxyalkyl alkoxysilane + an aminoalkyl-alkoxysilane, (b) an epoxyalkyl alkoxysilane + a low-molecular weight aliphatic primary or secondary mono-amine, (c) an aminoalkyl alkoxysilane + a low molecular weight monoepoxide, and (d) an epoxyalkyl alkoxysilane. .
The dispersion can optionally contain other additives, e.g.
lubricants, wetting agents and antistatic agents.

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10~9138 The polyurethanes which may be used accordlng to the invention are anionic or cationic in structure. It is prefer-red to use such polyurethane ionomers because these substances disperse spontaneously in w~ter so that the use of emul-sifiers can be di~pensed with. This con~titute~ an advantage because of the saving in costs and/or because it avoids undesirable side effects which are due to the property of ~mulsifiers of rendering substances hydrophilic, which is liAble to manife~t itself in glass fiber-reinforced thermo-plastic polyesters as a certain sensitivity to the act~on of water. As a consequence o~ the a~sence of emulsifi~rs the ~ilm-forming properties are better and the bonding to the substrate is improved.
Ionic polyurethanes are generally rererred to as polyurethane ionomers (see D. Dieterich et al in "Angewandte Chemie" 82, (1970), pages 53 to 63). The polyurethane ionomers which may be used according to the invention are thus polyurethanes which contain ionic sites at compar-atively large intervals, i.e. they are heteropolymers with a marked segmental structure. The polyurethane ionomers are high-molecular segment polymers which a~sociate in water to form macromolecular structures thus giving rise to particle weights of over 500.000. Due to interchenary interactions (Coulomb forces and hydrogen bridges) they have properties similar to those o~ crosslinked elastomers. Polyurethane ionomers in polar organic solvents spontaneously give rise to stable aqueous dispersions on the addition Or water, the ionomers forming the dlsperse pha~e, so that emulsifiers normally used can be dispensed with. After removal of the organic solvent the polyurethane ionomers are then available as dispersion~ free of emulsi~iers and solvents. It is an Le A 15 770 - 7 -:

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1089i38 important advantage Or the size useable in accordance with the invention that for this rea~on they contain neither emulsifiers nor organic solvents which may be harmful to the desired action Or the size or the coatlng compositions pro-duced rrom the sizes on the glass fibers in the polymer matrix.
The insolubility in water of coatings prccipitated from aqueous dispersions of polyurethane ionomers and the formation of these coatings themselves can be explained by the formation of hydrophobic linkages. This likewise explains the excellent ra~tness to aging Or the aqueous polyurethane lonomer disper-sions which is technically an important consideration.
One of the moQt striking properties Or the polyurethane ionomers is their excellent film-forming capacity, even at low temperature~, which is practi¢ally equivalent to that of solvent systems. Films rrOm these polymers have high elasti-city, tensile strength and abrasion-resistance, that is they meet the most important requirements made of ~ilm-rormi~6 agents ror use in sizes ~or glass-ribers. A further advantage of speci~ically anionic polyurethane ionomers is their re-sistance to electrolysi~ and their excellent compatibility with other polymer diQpersions and auxiliaries. This is Or very great importance in the production, handling and pro-cessing of sizes rOr glass fibers, since the ma~ority o~ such sizes contain two to three and orten considerably more com-ponents; thus good compatibility Or the individual components, in particular o~ the rilm-~orming agent which i8 present in the largest amount, i8 absolutely essential ~rom a technolo-gical and economical viewpoint. This also explalns why Le A 15 770 - 8 -1~)89138 special additives are claimed in German OS 1 922 441. Their use is intended to prevent non-ionic polyurethanes from pre-cipitating from their dispersions and settling on the size coating device; as a result of this happening the glass fibers issuing from the spinning noz~les break and production ~
is interrupted. .
Polyurethane ionomer dispersions can be prepared according to different processes known in the art, e.g. the acetone process ~ ~
or the melt dispersion process (cf. D. Dieterich and H. Reiff, ; ~ -Angew. makromol. Chemie 26~ 85, 101 (1972)). - ;
Dispersions of polyurethane ionomers of the kind described for example in "Angewandte Chemie" 82, 53 (1970) are preferred.
The ionomer dispersions obtained by the melt dispersion process (for example according to German OS 1 770 068 and German OS
1 913 271) are also particularly suitable.
-The best properties are obtained with those dispersions ; in which the dispersed particles have an average diameter of from 0.05 to 0.5 micron and an ionic group content of about 5 to 30 milliequiYalents per 100 g of dry material are also preferred.
Cationic or anionic polyurethane dispersions in which the disperse phase is at least partly microgel in character~are ~
~`~ partîcularly preferred. On the other hand, the mlcrogel character should not be too pronounced since the film-forming capacity may be otherwise impaired. Particularly suitable dispersions are ~ -~ :: i . . : .. :::
characterized in that they yield a slightly opalescent solution - when diluted with about 4 to 10 times their amount by weight of tetrahydrofuran. This slight and ~ 9 ~ ~ .
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¦ completely uniform turbidity is easily visible in a layer 2 cm deep, particularly when seen by reflected light. The turbi-dity may be more pronounced, but under no circumstances should the dispersion be allowed to retain a milky-turbid character when diluted with tetrahydrofuran. On the other hand, a com-pletely clear solution should likewise not be produced.
Dispersions which meet the above criterium undergo pronounced swelling when diluted with tetrahydrofuran with the result that when rlowing the surface of the slightly turbid solutions is not smooth, but optionally rough.
The criterium regarding the microgel character is appli-cable to those dispersions which have finished reactin~ and contain no more reactive groups.
Dispersions which contain reactive groups or reactive crosslinking agents, for e~ample those described in German ..
OS 1 770 o69 and German OS 1 91~ 271, are prefera.bly also partly microgel ln character when they are used as sizes ror glass ribers; however, they do not have to be crosslinked at all at the time of application. This is evident ~rom the formation of a clear solution on dilution with tetrahydrofuran.
When employing these dispersions which are not crosslinked, however, it must be ensured that a crosslinked coating ~orms through further reaction on the gla.ss riber. This means that , ,~ a sample Or the size employed must form a film after drying and condensing at 140C which is insoluble in ~0 ~ aqueous - tetrahydrofuran. Polyuretha.ne dispersions which fulfil the -~
abov~ criteria ca.n be prepared from a plurality of monomers monomer components in the greatest variety o~ weight ra.tios.
Il The variety Or possibilities available for synthetizing I Le A 15 770 - 10 -: J , . . ..... .... . . .
.'"' ' .' .'' ': ' polyurethane ionomers are known to those skilled in the art.
Hence products suitable in accordance with the invention may contain urethane groups as well as urea, amide, esterl ether, thioether, acetal biuret, ureide, allophanate, and carboimlde units. Polyester-polyurethanes, polyester-polyurethar.e ureas, polyester amide-polyurethanes and polyester ~mide-polyurethane ureas and polyester urethane biurets are especially preferred.
Pre~erred synthetizing components for the polyurethane dispersions used in accordance with the invention are:
l) polyester diols with molecular weights ranging from 500 to 3000, prepared rrom adipic acid, phthalic acidJ iso-phthalic acidJ tetrahydro-phthalic acid, hexahydrophthalic acid and ethylene glycol, butane diol, neopentyl glycol, hexane diol; a particularly good bond wlth glass i8 achieved with products which contain phthalic acld;
~- .

2) diisocyanates, in particular aliphatic or cycloallphatic diisocyanates, e.g. hexamethylene diisocyanate, xylylene, diisocyanate, isophorone diisocyanate, diisocyanato-di-~; cyclo-hexyl-methane;
~) chain-lengthening agents, such as the usual glycols, di-~ amines, as well as tert.-amino-glycols.for cationic and ! ~ sulphonato-glycols or sulphonato-diamines for anionic r~ dispersions.
Whilst anionlc polyurethane dispersions, particularly those with sulphonate groupsJ are distinguished by their exceptional stability and excellent compatibility with all kinds o~ additives, cationic dispersions provide a particular-ly true bond with glass. The adherence of many catlonic polyurethane lonomers to glass ~ibers is so excellent that !~
~ Le A 15 770 - ll -:-.~ ~ - - .. . . . .: ... . . ...

1~)89138 ' under favorable conditions the costly silane bonding agents normally employed may be dispensed wlth. This i8 ~rticularly true in the case of polyurethane ionomers synthetized on the base of phthalate esters.
In addition, those polyurethane ionomer dlspersions are Or especial interest which contain at least 0.1 ~ Or formal-dehyde or an equivalent amount o~ methylol compounds as these ensure the crosslinked character of the condensed size.
Dispersions prepared by the isocyanate polyaddition process contain formaldehyde (optionally bonded) generally in an amount Or o. 1 - o. 8 ~ based on the solids content; dispersions, which were synthetized from the initial oligomer stages by formaldehyde polycondensation, contair, a considerably larger amount of (bonded) formaldehyde, preferably 2 - 10 ~. -Exceptionally water-resistant polyurethane lonomers are those which have in addition been chemically crosslinked by polyisocyanates or other reactive components such as ~ormal-dehyde or its derivatives. Such polyurethane ionomers par-ticularly suitable for the glass fibers according to the invention.
Optimum properties are achieved by virtue Or the microgel or gel character Or the polyurethane ionomer size. The size ~-can be easily coated to glass riber substrates and rorms an excellent, closely adhering, homogeneous rilm even at low temperatures~ At the same time, the thermoplasticity Or the size is advantageously reduced, thereby resulting in j ~
~ good rreedom rrOm tackiness Or the resultant rovings as well ~ ~ .
as providing the composite materials of glass-riber and resin with excellent mechanical properties.

~ Le A 15 770 - 12 -,. ~

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This favorable combination of desirable propertles in a glass-fiber size has not been hitherto achieved by products known in the art.
To obtain optimum properties it is furthermore necessary that the dispersed polyurethane ionomers themselves should be capable of drying to yield high-molecular resins with good properties. Those polyurethanes are preferred which form a film having the following values when tl-e dispersion is poured on a rlat support and allowed to dry: -tensile strength: higher than 50 kp~cm2, preferably higher than 100 kp~cm elongation at break: lOG - 600 shore-~-hardness: 50 - 90 ~ swelling in water at 20C less than ~0 ~.
rl~ Dispersions of anionic polyurethanes are e~pecially ~ preferred, especially those which contain sulrOnate groups . , or carboxylate groups.
The concentration of the polyurethane dispersion ln a size suitable for use according to the invention ls about 1 to 15 ~ by weight, based on the p~lyurethane ~olid content. Con-~ centrations below about 1 % byIwelght produce only an insu~ficient l protective film on thc ribers, whereas concentrations higher ; ~ than about 15 ~ by weight result in exces~ively thick layers coating which weaken the composite material produced ;~ with these fibers. Moreover, it is prohibitive for reasons oi~ cost to apply larger quantities Or film-forming agents to the fibers. The concentration Or the polyurethane dispersion used in the size i8 pre~erably between about 3 and 7 ~ by weight. It is found in practice that when Guch a size is applied to fibers in the spinning process, the Le A 15 7(0 - 13 -;

~ -i 1~91;~8 dry fibers obtained nfter evaporation of the water are loaded with about 0.4 to 2,0 ~, preferably 0,5 to 1,5 ~ by weight o~ size con-stituents, the film-forming agent generally predominating in quantity. Size contents in this range are regarded as optimum for reinrorcing thermoplastic polyesters, both on technical grounds and out of economic considerations.
Although the molar ratios o~ the components in a combination bonding agent used according to the invention may range between about 5:1 and 1:5, it is advisable for economical reasons to use the more expensive component more sparingly, that i6 to say in combination types (a) and (b~ generally the silane component and in combination type (c) at present the epoxyalkyl trialkoxysilane, and to increase the prop-ortion Or the less expensive component accordingly withln the range o$ molar ratios indi¢ated above.
The concentratlon of the bonding agent in the size used according to the invention is about 0.05 to 1.5 ~ by welght, preferably about 0.15 to 0.75 ~ by weight. Concentrations i, above about 1.5 ~ by weight are uneconomical o~ account o~ the high cost Or the silane while at concentrations below about 0.05 % by weight the bonding agent ;s not suiriciently erfective. Concentrations Or between about 0. 05 and C.15 by weight are chosen ii application of the size to the elass fibers is not carried out during the spinning process, i.e. within fractions Or a second, but at some other stage, or example by impregnating the glass fibers in a sizing bath, a method which for practical reasons requires a much ~--Le A 15 770 - 14 -~ ' ~ - ' lVi~13~
.

longer time, during which much greater utilization of the size is possible than in cases where the size is applied during the ~pinning process.
Epoxyalkyl alkoxysilanes which may be used according to the invention include epoxyalkyl trialkoxysilanes, epoxy-alkyl-alkyldialkoxysilanes and epoxyalkyl-aryl-dialkoxy~ilanes~ -~
preferably where the alkyl ieties contain up to 6 carbon atams, especially aliphatic moieties of up to 4 carbon atom~
or cyclopentyl or cyclohexyl, and the aryl molety L~ phenyl.

~ -glycidoxypropyl trimethoxysilane and ~-(3,4-epoxycyclo-hexyl)-ethyl trimethoxysilane are preferred.
It is suitable to include a lubricant 1~
according to ~he invention. These lubricants may be chosen irom among the iollowing groups Or subætances:
polyalkylene glycols, hlgher iatty acid amides containing i about 12 to 18 carbon atoms, and polyoleiin dispersions.
1 Preferred polyalkylene glycol8 are tho8e wherein the alkylene ~! radical8 conta~n up to about 6~ e8pecLa11y up to about 4, carbon atom~, e.g. polyethylene glycol, polypropylene glycol, poly-ethylene-propylene glycol, etc~ Preferred polyolef~n8 ~ are homopolymer8 and copolymer8 Of a-ole~in~ containing up i; to about 6, e8pecially up to about 4, carbon atomB, e.g.

~ polyethylene, polypropylene, ethylene-propylene copolymer, etc.
`~ The lubricant is suitably used in concentrations oi about 0.05 to 1 ~ by weight. Concentrations in the upper region of this range would be ind~cated in particular if the ~ lubricant used is a polyoleiin dispersion. Values in the ! lower region oi thi~ concentratlon range are preferred ii Le A 15 770 - 15 -., 10~91;~8 the lubricant u~ed is a polyalkylen glycol or a higher fatty acid amide. If a polyolefine dispersion is used, preferably it i8 anionic or nonionic if the ~ilm-forming agent is an anionic polyurethane, and cationic or nonionic i~ the polyurethane is cationic, in order to prevent mutual coagulation of the di~persions in the size. Apart from this restriction, the choice of a suitable lubricant from the groups of substances mentioned above is not critical. The purpose of the lubricant is to facilitate subsequent processing of the glnss fibers but it has no material influence on the bonding action Or the sizes according to the invention, that is to say on the action which improves the mechanical properties o~ the glass fiber/polymer composite material.
Among the group of aminoalkyl alkoxysilanes which may be used according to the invention, it is preferred to use tho8e wherein the alkyl ~etie8 conta~n up to 6 carbon atom~, e~pecially aliph~tic moietie8 of up to 4 carbon atomB or cyclopentyl or cyclohexyl, e.g. ~-aminopropyl trialkoxy-silanes such as ~-aminopropyl triethoxys~lan~ aminopropyl trimethoxyæilane and (B-aminoethyl)-ar-aminopropyl trimethoxy-silane.
Low molecular weight, aliphatic monoamines which may be used according to the invention Include primary amines containing from 1 to 6 carbon atoms and secondary amines containing irom 1 to 5 carbon atoms per organic group, such as diethylamine, dipropylamine, dibutylamine, methyl ethylamine, methyl propylamine, methyl butylamine, ethyl ,, . :
~ - Le A 15 770 - 16 -, ' propylamine, ethyl butyl~mine, methyl amylamine, ethyl amylamine and diamylamine.
l.ow molecular weight monoepoxides which m~y be used according to the invention include alkylene oxides such as ethylene, propylene and butylene oxide, epihalogen hydrins such as epichlorohydrin and epibromohydrin, and aromatic mono-epoxides such ~s styrene oxide.
In reinforcing polycarbonate resins, although glass fibers which have been sized according to the invention with aqueous polyurethane dispersions in combination with an epoxyalkyl trialkoxysilane give rise to excellent propertie~, it is preferred to use bonding agent combinations in accordance with the above mentionel groups (a), (b), or (c) which have both an :: epoxy and an amino function.
Particularly advantageous comblnation bondi~g ~,~ agents of type (~ include ~-aminopropyl triethoxysilane and ~-glycidoxypropyl tr~methoxysilane or of ~-aminopropyl triethoxysilane and B-(3,4-epoxycyclohexyl)-ethyl trimethoxy-silane.
~ Particularly advantageous comb~nation bonding ;lt agents of type (~) include ~ glycidoxypropyl tri~eth~xysilane `~ or ~-(3,4-epoxycyclohexyl)-ethyl trimethoKysilane and }~ n-propylamine.

i~ A partlcularly sdvantageous combination bonding agent of type ~E) Lncludes ~-aminopropyl triethoxysilane and epichlorohytrin.
~ Le A 15 770 - 17 -.~

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Both the known types of E-, A-, C- and S-glass used for the manufacture of endless glnss filaments and the ~ known glass staple fiber products are suitable for producing5~ the glaæs fibers sized according to the invention. So-calleds high modulus and high strength glasses which have been developed for special purposes may also be used for producing ! sized glass fibers according to the invention. Among the vnrious types of glass mentioned above for the manufacture of glass filaments (so-called endless filaments), the E-glass fib~rs are the most important for the reinforcement of synthetic resins because in contrast to A- and C-glass, E-glass is pratically free from alkali, a property to which 't it owes its good electrical insulating properties and high resistance to water and alkalies. In addition, E-glass ibers are superior to A-glass fibers in their tensile strength and modulus of e~asticity.
E-, A-, S- and C-glass have the following chemical composition in percentages by weight (data obt~ined from Wende/Moebes/Marten "Glasfaserverst~rkte Plaste", VEB
~` Deutscher Verlag f~r Grundstoffindustrie Leipzig, 1969, 2nd edition, p. 74):

.: .
.

~!
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'~:: ' , ~089138 The sized glass ribers according to thc invention mny be used for reinforcing thermoplastlc reslns which contain polar groups regularly distributed in their chain structure.
By "polar groups" are me~nt groups which under the known conditions employed for incorporating sized glass ~iber into thermoplastic resins, are capable of forming such physical ~nd/or chemical bonds with the sized glass ~iber~
according to the invention that the glass fiberS can be demonstrated to have a distinct reinforcing effect on the resin. This can be proved e.g. by measurement of the flexural strength, impact strengt~ notched impact strength etc. on st~ndard test samples. The following are polar ,~; groups within this meaning: primary, secondary and tertiary amlno groups, amide and imide groups, carbonyl, oarboxyl, ester, ether, acetal, oxirane and oxetane groups and nitrile and sul~one groups. Resins which are particularly suitable for reinforcing with the sized glass fibers acc-ording to the invention are: polyamides, polycarbonates, ~ r thermoplastic polyesters such as polyethylene and poly-butylene terephthalates, styrene-acrylonitrile copolymers~
acrylonitrile-butadiene-styrene terpolymers and a¢rylonitrile-methyl methacrylate copolymers.
The process according to the invention will now be explained in more detail with the aid of the following Examples. -! ~
Le A 15 770 - 20 -~' .

... . . . . . . . . ..

, 101~9138 Example 1:

(a) Com~osition of the size:
.. _ Polyurethane-anionomer disper~ion No. 1 (solids content 40 %) 12.5 ~ by weight ~ 1 o ,~O,oy ,~
B ~-nmi.no triethoxysilane0.33 % by weight epichlorohydrin0.17 % by weight polyethylene dispersion (solids content 40 ~) 1.25 % by weight deioni2ed water85.75 ~ by weight (b) PreP~ration of Polyurethane anionomer dispersion No. 1 20~ g (0.125 mole) of a polyadipate of an equimolar ~ hexanediol-neopentyl glycol mixture (average molecular weight .. 1670) are dehydrated in a water ~et pump va.cuum at 120C for 30 minutes with stirring. The substance i8 le~t to cool to 70C
and 38 g (0.226 mole) of 1,.6-diisocyanatohexane are then a.dded.
5` ,~ When the exothermic reaction has died down, the reaction mixture is stirred for 2 hours at 120C. After cooling ..
to 70C, 700 ml oi acetone are added and the bath temp-erature ls adjusted to 60C so that the reaction mixture is kept at a temperature of 55C.
A chain-lengthening solution is prepared ~rom 13.75 g Or . an aqueous solution of æodium N-2-aminoethyl)-2-aminoethane ulfonate (solids content 43 % by weight) (0.0313 mole) s~ 1.90 g (0.0317 mole) o~ ethylene diamine and 58 g o~ water and added to the reaction mlxture which is kept at 55C. The mi~ture is stirred ~or 5 minutes and I~ 270 ml of distilled water are then added. The acetone is i~; then distilled Orr in a water jet pump vacuum.

t~ Le A 15 770 - 21 -,j ' :
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The ~inely divided anionic polyurethane dispersion obtained in this way h~s a ~olids content of 40 % by weight and, based on its ~olid content, it contains o.g6 % by w~ight of SO~e groups; it has a particle size of 150-200 mp.
The disperse phase shows microgel-character (slightly cloudy solution after dilution with tetrahydrofuran).
(c) Preparation of the size:
Approximately half the required quantity of water is introduced intoa mixing vessel. The polyurethane dispersion is added with stirring. The polyethylene dispersion, silane and epichlorohydrin are then added one after the other with continued stirring. After the addition of the remaining water, the pH of the size is adjusted to 5.9 - 6.0with acetic acid.
(d) Preparation of the composite material of ~laæs fiber and polvcarbonate and testine the material for discoloration and mechanical properties:
~ E-glass ~ibers impregnated in a conventional manner i with the size used according to the invention are fed in the form of chopped strands 6 mm in length, each composed of 400 in~ividual filaments with a diameter oi~ 12 ~, into D a double-sha~t extruder where they are mixed with molten ~ polycarbonate "Makrolon 3200~ (Manufacturers: Bayer AG, Leverkusen) and extruded. The resulting Makrolon granulate which contains 20 % by weight of glass fib~rs i8 used to produce test samples in a screw extruder. The following mechanical properties are determined on the~e samples according to the standards mentioned:
Flexural strength DIN 53452 1627 kp/cm2 Impact strength DIN 53453 61.8 cmkp/cm2 Notched i~pact strength DIN 53453 15.0 cmkp/cm2 Le A 15 770 ~- 22 -i~r ~r~ ~e ~ ~

108~3138 The glass fiber-reinforced polycarbonate i9 virtually colorless. The superior quality of glass fibers sized according to the invention is clear from the absence of any undesirable discolora.tion in the reinforced poly-carbonate and the hitherto unobtainable level of the mechanical properties indicated above.
Example 2:
The techn~cal advance of the invention will now be illustrated more clearly with the aid of a comparison with a glass fiber-reinforced polycarbonate (nMakrolon 3200") which has been reinforced in the same way as indicated above with 20 % by weight of ordinary commercial E-glass fibers in the form of chopped strands 6 mm in length. These glass fibers were described by the manu-facturers as optimum for the reinforcement Or polycarbonates.

,.~,.~, ~:~: The following mechanical properties were measured on test samples o~ this material:

Flexural ~trengthDIN 53453 1591 kp/cm2 ~;

. Impact strengthDIN 5345~ 49.7 cmkp/cm .~
.~. . Notched impact strength DIN 53453 9.8 cmkp/cm The glass fiber-relnforced polycarbonate has a distinct yellow discoloration. This discoloration proves : i!i . ~ that the commercial glass fibers are inferior to fiberæ
. ~ whioh have been sized according to the invention.since in both cases E-glass was used as thelreinfor~ material and "Makrolon 3200~ as the matrix and the operating conditions and test conditions were completely identical.
:i i.: ' ~ Le A 15 770 - 23 -.: -:

:
, ;, .
.-:~ - . -. : .. . .

~ iV1~9138 Ot~r C~ eæ nceor~ing to the inventlon nr-? descrlbed ln t~ nml)Ies be]ow. PrepMrntlon of thc~e ~t'~e9 i~ earried o~lt hy t~l~ m~thod ne~rlbed in EXAm~le 1. Manuructure of the glaFffs ~i~r-reinrorc~d pnlyc~rbonntefs from "MAkrolon ~0~!" nnd E-glnss fiber ~trands which hnve been si~ed in ~ nffnnner wlth the sizc nccording to the lnvention (length of strnn~s 6 mm, 400 :Individual filaments with a diameter of 1' ~ff ) nnd t~st~ng of thc samples are also carried out ~s deseribcd in Examp]e 1. The gla~s content of the rein- :
forced polycarbonAtes is in each ca~e 20 % by weight. The composition of the size~, the mechanical values round on the test samples and the color of the reinforced poly-carbonates are given in the following Example~ff.
Example 3:
(a) Composition o~ size:
Polyurethane anionomer dispersion No. 2 (solids content 30 %) 16.7 % by weight -glycidoxypropyl trimethoxysilane 0.25 % by weight :~
Polyethylene dispersion (solids content 40 %) 1.25 % by weight Deionized water 81.8 % by weight (b) PreParation Or polYurethane~anionomer disPersion No. 2 Reaction mixture:
(1) 5080 g of hexanediol-neopentyl glycol-polyadipate, .i:
average molecular weight 1980 !
(2) 980 g Or an adduct of l,l,l-trimethylolpropane and tetrahydrophthalic acid anhydride used in a molar ratio Or 1:1.2; 80 % in methyl isobutyl ~; ketone :

(3) 350 g Or urea Le A 15 770 - 24 -. ~

(4) 200 g of 2-dimethylaminoethanol

(5) 1000 g o~ 1,6-diisocyanatohexane

(6) 1000 ml o~ methyl isobutyl ketone (~IIBK)

(7) 170 g of a polyether of ethylene oxide and propylene oxide started on glycerol

(8) 70 g of ethoxylated nonyl phenol

(9) 500 g of 30 ~ formaldehyde in water 14500 ml of water Method:
The chain-lengthening agent (2), urea (3) and MI~K (6) are added to the dehydrated ester (1). The diisocyanate (5) ie added at 35C and the mixture is stirred for 1~ hours at 60 to 68C. The mixture is then heated to 135C and stirred at this temperature ror 1 hour. The polyether (7) and ethoxylated nonylphenol (8) are added to the melt. The mixture is dispersed by stirring at a rate o~ 100 revs. per ~ ~-min. 2.5 liters o~ water are added with the amine (4) in f 2 minutes, the temperature being thereby lowered irom 95C to 85C. The mixture i8 then stirred first ior 1 hour at 80C and then ror 1 hour while it is cooled with running water. A 32 ~ PU dispersion with pH = 7 and FBV4 = 26" is obtained. The dispersion is dlluted to 30 %. It is inderinitely stable in ~itorage at room ,i, ~
temperature. The dispersion when dried and heated to 140C

yields a ~ilm insoluble in 80 ~ tetrahydrofuran.

(c) Mechanical properties o~ the test sam~le:

Flexural strength DIN 53452 1704 kp/Cm2 Impact strength DIN 53453 57.4 cmkp/cm2 ~: .
Notched impact strength DIN 53453 11.0 cmkp/cm2 Le A 15 770 - 25 -~",,,.,,, . , - ,

10~9138 y (d) Color:
Virtually unchanged Example 4:
,, (a) Composition of the .size: -Polyurethane dispersion No. 1 (solids content 40 ~) 12.5 % by weight ~-aminopropyl triethoxysilane 0.~5 % by weight ~-glycidoxypropyl trimethoxysilane 0.25 % by weight Polyethylene dispersion ~solids content 40 %) 1.25 % by weight DeioniZed water 85.75 % by weight (b) Mechanical Properties o~ the test sam~le:
::
Flexural strength DIN 53452 1677 kp/cm2 Impact strength DIN 53453 55.o cmkp/cm2 Notched impact strength DIN 53453 15.8 cmkp/cm2 (c) Col~:
Vlrtually unchaneed . .1 Example 5:
(a) Composition o~ the size:
Polyurethane dispersion No. 1 (solids content 40 ~) 12.5 % by weight -glycidoxypropyl trimethoxysilane 0.4 % by weight propylamine 0.1 % by weight , . Polyethylene dispersion (solids content ; 40 %) 1.25 % by weight Deionized water 85.75 % by weight (b) Mechanical Properties o~ the test samPle:
Flexural strength DIN 53452 1659 kp/Cm2 Impact ~trength DIN 53453 59.4 cmkp/cm2 Notched impact strength DIN 53453 16.1 cmkp/cm2 , :~ Le A 15 770 - 26 -' . ' `. :' ..~
i :. . . . . . . . . ..

1~89138 (c) Col~r:
Virtually unchanged Example 6:
(a) Composition of the size:
Polyurethane dispersion No. 1 (solids content 40 %) 12.5 % by weight ~-aminopropyl triethoxysilane 0.25 % by weight ~-(3,4-epoxycyclohexyl)-ethyl trimethoxysilane 0.25 % by weight Polyethylene dispersion (solids content 40 %)1.25 % by weight Deionized water 85.75 % by weight (b) Mechanical Properties of the test sample:
Flexural strength DIN 534521739 kp/cm Impact strength DIN 5345357.0 cmkp/cm2 Notched impact strength DIN 5345316.1 cmkp/cm2 (c) Color:
Virtually unchanged ;
Example 7:
(a) Composition of the size used accordin~ to the invention:
Polyurethane anionomer dispersion No. 3 -~ solids content 40 %)12.5 % by weight aminopropyl triethoxysilane0.5 % by weight Polyethylene 1.25 % by weight ~; Deionized water 85.75 % by weight (b) PreParation of polyurethane anionomer dispersion No. 3:
209 g (0.125 mole) of a hexanediol-neopentyl glycol-polyadipate (average molecular weight 1670) are dehydrated ,~ ~
in a water jet pump vacuum at 120C with stirring for ~ 30 minutes. The substance is left to cool to 70C and ,~ 38 g (0.226 mole) of 1,6-diisocyanatohexane are added. When Le A 15 770 - 27 -. .
, ~

913~

the exothermic reaction has died down, the reaction mixture is stirred for 2 hours at 120C. After it has cooled to 70C, 700 ml of acetone are added and the bath temperature i9 ad~justed to 60C so that the reaction mixture 18 kept at a temperature of 55C.
A chain-lengthening solution is prepared rrom 13.75 g of an aqueous solution of sodium N-(2-aminoethyl)-2-amino-ethane sulfonate (æolids content 43 ~ by weight) (0,0313 mole), 1.90 g (0.0317 mole) of ethylene diamine and 58 g of water, and this solution is added to the reaction mixture which is kept at a temperature of 55C. The mixture is then stirred for 5 minutes and 270 ml oi distilled water are added. The acetone is then dist~lled Gff in a water jet pump vacuum.
The finely divided, anionic polyurethane dispersion obtained has a solids content of 40 % by weight and, based ~-on the solids content, it contains 0.96 ~ by weight of S03e groups; it has a particle æize of 150 - 200 nm.
~c) PreParation of the size:
Approximately half the required quantity of water is introduced into a mixing vessel. The polyurethane anionomer dispersion is added with stirring. The polyethylene dispersion and the silane are then added one after the other with continued stirring. After addition of the remaining water, the pH Or the size is adjusted to 5.9 - 6.0 with acetic acid.
(d) Testin~ of the reinforcin~ effect of ~lass fibers Droduced accordin~ to the invention in polyamide: -E-glass iibers treated according to the invention with the size described above are incorporated in the form oi Le A 15 770 - 28 -~, ".

, 1(~8~13t~

chopped strAnds 6 mm in length, composed of 400 individual filaments each with a diameter of 12 ~, into nylon-6 B ` ( Durethan BK 31 F", Manufacturers: Bayer AG, Leverkusen) ~ in a double-shaft extruder. The glass content of the glass fiber-reinforced polyamide is 35 ~. Test samples are produced from this glass fiber-reinforced material in an injection moulding machine and used to test the mechanical properties in accordance with the standard~ mentioned below:

Flexural strength DIN 53 452 2767 kp/cm2 Impact strength DIN 53 453 68.7 cm kp/cm2 Notched impact strength DIN 53 453 13.4 cm kp/cm2 Example 8:
(a) Composition of the size used accordin~ to the invention:
Polyurethane anionomer dispersion No. 3 (solids content 40 %) 12.5 ~ by weight ~-glycidoxypropyl trimethoxysilane 0.25 % by weight Deionized water 87.25 ~ by weight Preparation of the size and testing o~ the glass ribers according to the invention for their reinforcing effect in polyamide are carried out as described in Example 7. The following mechanical properties are tested:
Flexural strength DIN 53 452 2748 kp/cm2 Impact strength DIN 53 453 67.8 cm kp/cm2 Notched impact strength DIN 53 453 13.5 cm kp/cm2 ExamPle 9:
(a) Composition o~ the size used accordin~ to the invention:
Polyurethane anionomer dispersion No. 3 (solids content 40 ~) 12.5 % by weight .
Le A 15 770 - 29 -~e ~c~ r k~

~089138 ~-aminopropyl triethoxysilane 0,33 ~ by welght Epichlorohydrin 0.17 % by weight Polyethylene dispersion (solids content 40 ~) 1.25 % by weight Deionizel water 85.75 % by weight Preparati~n of the size and testing of the glass~ibers according to the invention for their reinforcing effect in polyamide are carried out as indicated in Example 7. ~he following mechAnical properties are exhibited:
Flexural strength DIN 53 452 3031 kp/cm2 Impact strength DIN 53 453 72.1 cm kp/cm2 Notched impact strength DIN 53 453 17.8 cm kp/cm2 ExamDle 10: ~:
Size not according to the invention but prepared according to German OS No. 2 300 368, Example 4, from the followin&
component~:
Urethane latex (nonionic) X-1033 (solid~ content 40 %) Manufacturers: Wyandotte Chemical Corp., Wyandotte, Mich., USA) 12.5 % by weight ~:

~-aminopropyl triethoxysilane 0.25 % by weight Polyolefin emulsion (solid~ content 40 ~) 1.0 ~ by weight ~ .
Thi~ size i8 prepared by the method described in Example 1 o~ German OS No. 2 300 368 and used for finishing glass fibers by the method described in Example 7. Hereinabove incorporation ~.

of the gla8~ fibers into nylon-6 ("Durethan BK 31 F") and ~: :
testing of the mechanical properties are also carried out Le A 15 770 - 30 -, ~089138 in exactly the same way as described in Example 7. The following mech~nical properties were measured:
Flexural strength DIN 53 452 2697 kp/cm~
Impact ~trength DIN 53 453 66.0 cm kp/cm2 Notahed impact strength DIN 53 453 12.8 cm kp/cm2 The results of Example 7 to 10 show clearly the superiority of the sizes according to the invention over a size which contains a nonionic polyurethane instead of one of the polyurethane anionomers used according to the invention.
Other sizes according to the invention are described in Examples 11 to 14 below. Preparation Or these sizes is carried out by the method described in Example 7. Manu~acture of the glass fiber-reinforced polyamides and testing Or the mechanical properties are also carried out as described in Example 7 and there~ore only the compoæition oi the size and the mechanical properties will be indicated. The glass content Or the glass fiber-rein~orced polyamides iæ
in each case 35 ~ by weight.
Example 11:
(a) Composition of size:
Polyurethane anionomer dispersion No. 312.5 ~ by weight -aminopropyl triethoxysilane 0.25 ~ by weight -glycidoxypropyl trimethoxysilane 0.25 % by weight Polyethylene dispersion (solids content 40~) 1.25 % by weight Deionized water 85.75 % by weight Le A 15 770 - 31 -108~)13~

(b) Mechanical properties of the test samPles:
Flexural strength DIN 53 452 2976 kp/cm2 Impact strength DIN 53 453 66.3 cm kp/cm2 Notched impact strength DIN 53 453 14.6 cm kp/cm2 Example 12:
(a) ComPosition of size:
Polyurethane anionomer dispersion No. 31205 ~ by weight -aminopropyl triethoxysilane 0.25 % by weight ~-(3,4-epoxycyclohexyl)-ethyl trimethoxysilane 0.25 ~ by weight Polyethylene dispersion 1.25 ~ by weight Deionized water 85.75 % by weight (b) Mechanical Properties of the test samPle:
Flexural strength DIN 53 4522967 kp/cm Impact strength DIN 53 45370.9 cm kp/cm2 Notched impact strength DIN 53 45316,5 cm kp/cm2 ~-Example 13:
(a) Com~osition o~ size:
Polyurethane anionomer dispersion No. 312.5 ~ by weight ~ -glycidoxypropyl trimethoxysilane 0.4 % by weight n-propylamine 0.1 % by weight -Polyethylene dispersion (solids content 40%)1.25 ~ by weight Deionized water 85.75 % by weight (b) Mechanical properties of the test samples:
Flexural strength DIN 53 452 2793 kp/cm2 Impact strength DIN 53 453 69.6 cm kp/cm2 Notched impact strength DIN 53 453 13.9 cm kp/cm2 Le ~ 15 770 - 32 -~,~ ...... . . .. . . .
. . . - . . , , : . : . . :
,. , . -: .

lV~91~B

Ex~mple 14:

(a) Composition of size:
-Polyurethane anionomer dispersion No. 4 (solids content 40 %) 12.5 % by weight ~ -aminopropyl triethoxysilane 0 25 % by weight Epichlorohydrin 0.25 % by weight Stearic acid ~mide 0.05 % by weight Deionized water 86.95 % by weight (b) Preparation of ~olyurethane anionomer dispersion No. 4 Reaction mixture: 5080 g of hexanediol-neopentyl glycol-polyadipate with an average molecular weight Or 1980, 980 g of an adduct Or ~ trimethylolpropane and tetrahydrophthalic acid anhydride in a molar ratio Or 1:1.2; 80 ~ in methyl isobutyl ketone, 350 g Or urea, 200 g Or 2-dimethylaminoethanol, 1000 g o~ 1,6-diisocyanatohexane, 1000 ml Or methyl i~obutyl ketone (MIBK), 170 g Or a polyether Or ethylene oxide and propylene oxide started on glycerol, 70 g Or ethoxylated nonyl phenol, 500 ml Or 30 % iormaldehyde in water and 14500 ml Or water.
Method Or preparation: The chain-lengthening agent, urea and MIBK are added to the dehydrated ester. The diisocyanate i 9 added at 35C and the mixture is ~tirred at 60C (Triax 68) ror 1~ hours. It i9 then heated to 135C and stirred at this temperature for 1 hour. The polyether and the ethoxylated Le A 15 770 _ 33 _ , .: . .:

nonyl phenol are added to the melt which is then dispersed by stirring at a rate of 100 n/min. 2.5 liters oi water are added with the amine in 2 minutes. 7 liter8 o~ water followed by 5 llter~ of w~ter with formaldehyde are added in 7 minutes, the temperature dropping from 95C to 85C. The mixture is then stirred for 1 hour at 80C, the temperature being kept down by cooling with running water, A 32 ~ PU dispersi~n with a p~
of 7 and FBV4 - 26" is obtained. The dispersion was diluted to 30 %, It is inderinitely stable at room temperature.
(c) Mechanical properties of the test samples:
Flexural strength DIN 53 452 2856 kp/cm2 Impact strength DIN 53 453 70.3 cm kp/cm2 Notched impact strength DIN 53 453 14.2 cm kp/cm2 Example 15:
The following mechanical properties are found on test samples o~ nylon-6 ("Durethan BK 31 F") which ha~ been reinforced with 35 S Or commercial E-glass fibers in the iorm of chopped gtrands (length 6 mm) which are described as p~rtlcul~rly ~u~table for the rein~orcement of polyamides:
Flexural strength DIN 53 452 2544 kp/cm2 Impact strength DIN 53 453 '61.6 cm kp/cm2 Notched impact strength DIN 53 453 11.0 cm kp/cm2 When the mechanical properties obtained in Example 7 to 9 and 11 to 14 ~or nylon-6 which has been reinforced with glass ribers according to the invention are compared with the mechanical propertie~ obtained in Example 15 ~or the same nylon-~ which has been reinforced with ordinary commercial E-glass fibers in the same proportion by weight Le A 15 770 - 34 -- `"~
1~9138 (35 % by weight), the superiority of the size according to the invention can be clearly seen.
Example 16:
(a) Composition Or the size used accordin~ to the invention:

Polyurethane anionomer dispersion (sol~ds content 40 %) 12.5 ~ by weight (3,4-epoxycyclohexyl)-ethyl trimethoxysilane 0.25 ~ by weight Polyethylene dispersion (solids content 40~) 1.25 ~ by weight Deionized water 86.0 % by weight (b) Preparation of the Polyurethane anionomer disPerslon 209 g (0.125 mde) o~ n hexanediol-neopentylglycol-polyadipate (average molecular weight 1670) are dehydrated in a water jet pump vacuum at 120C for 30 minutes with stirring. The substance is leit to cool to 70C and 38 g (0.226 mole) o~ 1,6-diisocyanatohexane are then added. When the exothermic reaction has died down, the reaction mixture i8 stirred for 2 hours at 120C. When the reaction mixture has cooled to 70C, 700 ml oi acetone are added and the bath temperature is ~d~usted to 60C so that the reaction mixture is kept at a temperature Or 55C.
The chain-lengthening solution ~s prepared from 13.75 g of an aqueous solution of sodium N-(2-aminoethyl)-2-aminoethane sul~onate (solids content 43 S by weight) (0.0313 mole), 1.90 g (0.0317 m~e) oi ethylene diamine and 58 g oi water, and added to the reaction mixture which i 8 kept at 55C. -The mixture is then stirred ior 5 minutes and 270 ml oi distilled water are added. The acetone is then distilled oii in a water jet pump vacuum.

Le A 15 770 _ 35 _ 1~)89138 The finely divided, anionic polyurethane dispersion obtained has a solids content of 40 % by weight, and, based on the solids content, it contain~ o.g6 % by weight of S03e groups; it has a particle size of 150 to 200 nm.
(c) Preparation and aPPlication of the size About hal~ the required quantity o~ water is introduced into a mixing vessel. The polyurethane anionomer dispersion and the polyethylene dispersion are added one after another with stirring. The pH of the mixture is then adjusted to 5.0, A hydrolyzate of (3,4-epoxycyclohexyl)-ethyl trimethoxy-silane prepared in accordance with the instructions of the silane manufacturer (Union Carbide Corporation, New York) is then added. After about 15 minute~ stirring, the size is ready for use. It is transferred to a conventional glass fiber sizing apparatus where it i8 applied in known manner, e.g. by a system of rollers or spray nozzles, to glass fibers drawn from a conventional spinning die~ and the glass fibers produced according to the invention are combined to form one or more strands and wound on a rot-atlng drum and then dried at temperatures between 100 and 150C.
(d) Processin~ oi the ~lass fiber strands. their incor~oration into Pol~utylene terePhthalate. manufacture of the test samPles and mechanical properties of the test samPles ~; When drying has been completed, the glass fiber strand ~-packages (spinning cakes) are wound off and ~hopped into lengths oi about 6 mm in a--suitable cutting apparatus. The chopped strands are mixed with molten polybutylene tereph-thalate at 260C in a double-shaft extruder.
.

Le A 15 770 - 36 - ~-, .~
'~ ' ` ., The mixture o~ glass fibers and polymer is extruded and granulated in a oonventional manner. Test samples are produced from the granulate (glas~ content 29.4 %) in a screw extruder and used to determine the following mechanical properties in accordance with the standards indicated:
Impact strength DIN 53 455 47.0 cmkp/cm2 Notched impact strength DIN 53 453 10,8 cmkp/cm2 Flenlral strength DIN 53 452 1856 kp/cm2 Tensile strength DIN 53 455 1520 kp~cm2 Tension -E-modulus DIN 53 457103 400 kp/cm2 Example 17:
(a) Composition of the size used accordin~ to the invention Polyurethane cationomer dispersion (solids content 43~)11.6 % by weight ~ -glycidoxypropyl trimethoxysilane0.25 % by weight -Stearic acid amide 0.05 ~ by weight Deionized water 88.1 % by weight (b) PreParation of the Polyurethane cationomer disPersion 19 200 g (11.361 mo~)of a polyester o~ equimolar adipio ~cld:
phthalic acid and ethylene glycol are dehydrated in a water jet pump vacuum at 120C for 2 hours with stirring. The polyester is cooled to 70C and 2 880 g (17.143 mole) Or 1,6-diisooyanatohexane are added. When the exothermic reactlon has died down, the reaction mixture is stirred for a iurther 2 hours at 120C. The mixture is left to cool to 70C and then diluted with 3 liters of acetone.
The temperature is subsequently regulated so that the reaotion is kept at 55C. 465 e (3.908 mole) of N-methyl- `
diethanolamine are dissolved in 1.5 liters of acetone and Le A 15 770 - 37 -`~-`` lV89138 ndded to the reaction mixture which is subsequently diluted with a further 1.5 liters of acetone. A further 9 liters of acetone are added in the course of the next 3 hours to reduce the viscosity. 453 g (3.595 mole) Or dimethyl sul~te in 1.5 lit~rs of acetone flre then added to the acetonic polyurethane solutlon which is then stirred for a further 30 minutes before a chain-lengthening solution consistlng of 165 g (2.754 mole) of ethylene diamine, 7.5 g (0.073 mole) o~
diethylene triamine and 1600 g of distilled w~ter is added.
An IR-spectrum taken 30 minutes later no~longer shows an NC0-band.
450 ml o~ 20 ~ phosphoric acid and 30 liters of -~
distilled water previously heated to 50~C are added to the reaction mixture. The acetone is then distilled o~f in a water jet pump vacuum. 300 cc of a 40 ~ aqueous formaldehyde solution are added to the resulting finely divided dispersion which is then stirred for 1 hour at 50C and iinally left to cool with stirring.
A finely divided, cationic polyurethane dispersion with a sQlids content oi 43 ~ and pH Or 3 i8 obtained. It contains 0.23 % by weight Or quaternary nitrogen, based on the solids content, ~nd its particle size is 75 - 100 ~ .
The preparation and application of the size, processing o~ the glass ~ibers and their incorporation into polybutylene terephthalate and the production and testing of the test ~ ~amples are carried out as described in Example 16.
:` ~ ' , :

Le A 15 770 - 38 -`` 108!,~138 (c) Mechanical_properties of the test samples: ~lass content 28.3 % by wei~ht Impact strength DIN 53 455 46,8 cmkp/cm Notched impact strength DIN 53 453 11,1 cmkp/cm Flexural strength DIN 53 452 1856 kp/cm2 Tensile strength DIN 53 455 1511 kp/cm2 Tension-E-modulus DIN 53 457 104 200 kp/cm2 ExamPle 18:
Glass fiber~ are impregnated by the same method as described in Example 16 with a size which is not in accordance with the invention, consisting of the following conventional composition for glass fiber sizes:
Polyvinyl acetate dispersion (solids content 5 ~) lo ~ by weight -methacryloxypropyl trimethoxysilane 0.25 ~ by weight Stearic acid amide 0.05 % by weight Deionized water 89.7 ~ by weight The glass fibers are then used in the same way as in Examples 16 and 17 for reinforcing the same polybutylene terephthalate as,in these examples. Test samples made of the reinforced material (glass content 30.2 ~ by weight) are found to have the following mechanical properties:
Impact strength DIN 53 455 41.4 cmkp/cm2 Notched impact strength DIN 53 453 8.9 cmkp/cm2 Flexural strength DIN 53 452 1744 kp/cm2 Tensile strength DIN 53 455 1087 kp/cm2 ~-Tension-E-modulus DIN 53 457 85 400 kp/cm2 ':
';''-Le A 15 770 - ~9 -~ .

lV~9 1 3 8 Example 19:
Glass fibers are impregnated by the same method as described in Example 16 with a size which i~ not in accordance with the invention, consisting oi the following commercial composition:
Styrene acrylonitrile copolymer dispersion (solids content 4 %)12.5 % by weight ~ -glycidoxypropyl trimethoxysilane0.25 ~ by weight Polyethylene dispersion (solids content 40 %) 1.25 ~ by weight The fibers are then added in the same way as indicated in Example 16 for reinforcing the same polybutylene tere-phthalate. Test sample~ manufactured ~rom the reinforced material (glass content 29.6 % by weigpt) are found to have the following mechanical properties:

Impact strength DIN 53 45530.3 cmkp/cm2 Notched impact strength DIN 53 453 6.6 cmkp/cm2 Flexural strength DIN 53 4521478 kp/cm2 Tensile strength DIN 53 455 960 kp/Cm2 Tension-E-modulus DIN 53 45791 500 kp/cm2 A comparis ~ of the mechanical properties shown in B Examples 16~ 17 and 1~ which are obtained when using the process according to the invention with the mechanical properties shown in E~amples ~ and ~ which are obtained ?
when using methods not in accordance with the invention for preparing sized glass fibers clearly shows the superiority of glass fibers produced according to the invention for the manufacture of glass fiber-reinforced polybutylene tere-phthalate.
Le A 15 770 - 40 _ ~0 ~ 3 J~
B Exa~ple ~ proves that, in order that sized gla~s ribers will have maximum reinforcing effect in thermoplastic polyesters, it is not sufficient to use an epoxysilane as bonding agent and any film-forming agent in a size, as described in German OS No. 2 206 804. Rather it is of decisive importance to employ special combinations of bonding agents and f~lm-forming agents in the size, as employed in accordance with the invention~ particularly since a size for glass fibers generally contains ten to forty times as much film-forming agent as bonding agent. Example 2ff~proves that an unsuitable film-forming agent considerably impairs the advantageous effect of a bonding agent and therefore distinctly reduces the reinforcing effect of the glass fibers.
It will be appreciated that the in6tant speclfication and examples are set forth by way of illustration ~nd not limitation, and that various modlficat$ons and changes m~y be m~de without departing ~:
irom th ~pLrlt and cope oi the present inventLon.

' -`

-,:

Le A 15 770 - 41 -::

, , . : ,.; ...
,,~ . ., . ,: , . ,

Claims (17)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. An aqueous dispersion suitable for use as a sizing composition for glass fibers comprising a polyurethane ionomer as a film-forming agent in a concentration of about 1 to 15% by weight, said polyurethane ionomer being characterized by (a) having an average particle size of about 0.05 µ
to 0.5 µ, (b) having an ionic group content of about 5 to 30 milliequivalents per 100 g, and (c) being capable of forming a film when dried which has a tensile strength of at least about 50 kp/cm2 , an elonga-tion at break of about 100-600%, a Shore-A-hardness of about 50-90, a swelling in water of less than about 30%, and being insol-uble in 80% aqueous tetrahydrofuran after heating to 140°C, the aqueous dispersion further containing an epoxy-containing bonding agent, said bonding agent being present in a concentra-tion of about 0.05 to 1.5% by weight and being selected from the group consisting of (a) an epoxyalkyl alkoxysilane + an aminoalkyl-alkoxysilane, (b) an epoxyalkyl alkoxysilane + a low-molecular weight aliphatic primary or secondary monoamine, (c) an aminoalkyl alkoxysilane + a low-molecular weight monoepoxide, and (d) an epoxyalkyl alkoxysilane.

2. An aqueous dispersion according to claim 1, wherein the polyurethane is an anionomer.

3. An aqueous dispersion according to claim 1, wherein the polyurethane is a cationomer.

4. An aqueous dispersion according to claim 1, wherein the polyurethane ionomer of the disperse phase is at least partly microgel in character, which microgel is fully reacted and con-tains no reactive groups.

5. An aqueous dispersion according to claim 1, wherein the polyurethane ionomer of the disperse phase contains reactive groups or reactive crosslinking agents.

6. An aqueous dispersion according to claim 5, contain-ing about 0.1 to 10% of formaldehyde based on polyurethane solids as a crosslinking agent.

7. Glass fiber sized with a polyurethane ionomer accord-ing to claim 1.

8. E-glass fiber sized with a dispersion according to claim 1 and carrying about 0.4 to 2% by weight of polyurethane ionomer plus epoxy-containing bonding agent.

9. A thermoplastic resin reinforced with glass fiber according to claim 7.

10. A thermoplastic resin selected from the group con-sisting of polyamides, polycarbonates, polyesters, styrene-acrylonitrile copolymers, acrylonitrile-budadiene-styrene ter-polymers and acrylonitrile-methyl methacrylate copolymers rein-forced with E-glass fiber according to claim 8.

11. An aqueous dispersion suitable for use as a sizing composition for glass fibers comprising a polyurethane cationomer obtained from aliphatic or cycloaliphatic diisocyanates and phthalic ester groups containing polyhydroxy compounds as a film-forming agent and present in a concentration of about 1 to 15% by weight, said polyurethane cationomer being characterized by (a) an average particle size of about 0.05 µ to 0.5 µ, (b) an ionic group content of about 5 to 30 milli-equivalents per 100 g, and (c) a film-forming capability when dried, this film having a tensile strength of at least about 50 kp/cm2, an elong-ation at break of about 100 to 600%, a Shore-A- hardness of about 50-90, a swelling in water of less than about 30%, and being insoluble in 80% aqueous tetrahydrofuran after heating to 140°C, the aqueous dispersion further containing an epoxy-containing bonding agent, said bonding agent being present in a concentra-tion of about 0.05 to 1.5% by weight and being selected from the group consisting of (a) an epoxyalkyl alkoxysilane + an aminoalkyl-alkoxysilane, (b) an epoxyalkyl alkoxysilane + a low-molecular weight aliphatic primary or secondary mono-amine, (c) an aminoalkyl alkoxysilane + a low-molecular weight monoepoxide, and (d) an epoxyalkyl alkoxysilane.

12. An aqueous dispersion according to claim 11, wherein the polyurethane cationomer of the disperse phase is at least partly microgel in character, which microgel is fully reacted and contains no reactive groups.

13. An aqueous dispersion according to claim 11, wherein the polyurethane cationomer of the disperse phase contains re-active groups or reactive crosslinking agents.

14. An aqueous dispersion according to claim 13, contain-ing about 0.1 to 10% of formaldehyde based on polyurethane solids as a crosslinking agent.

15. Glass fiber sized with a polyurethane cationomer according to claim 11.

16. E-glass fiber sized with a dispersion according to claim 11, and carrying about 0.4 to 2% by weight of polyurethane cationomer plus epoxy-containing bonding agent.

17. A thermoplastic resin selected from the group con-sisting of polyamides, polycarbonates and polyesters reinforced with E-glass fiber according to claim 16.