CH642034A5 - WINDING OF GLASS FIBERS CARRYING A PRIMER COMPATIBLE WITH POLYOLEFINS AND GOOD STORAGE. - Google Patents

Description

The invention described here relates to the treatment of glass fibers, and more particularly to the treatment of glass fibers during or after an aqueous finish which prepares the fibers for their bond with polyolefins, with the aim of reinforcing the polyolefin materials, said primer having a long shelf life, which can be used for prefabricated materials.

It is known that glass fibers in the form of continuous strands, fibers or webs can be used successfully to reinforce polyolefins, and it is known that, without effective coupling between glass and polyolefin, the adhesion between both will be weak and separation will occur under tensile or shear forces. It is also known that the affinity of glass for water aggravates the weakness of the bond when the glass is inadequately bound to the polyolefins.

A manufacturing process has been revealed which allows glass to be bonded to lower olefins which are essentially crystalline plastics formed from monomers which have three or more carbon atoms. As published in US Patent No. 3013915, column 2, lines 38-46, the bonding of glass to polyolefins can be improved by cleaning the surface of the glass, applying a coupling agent, treating with a chemical agent which is a source of dehydrogenating or oxidizing radicals, bringing the

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642,034

glass and polyolefins, then uniting by melting, heating the polyolefin above its melting point, to assemble. In column 4, lines 16-19, the publication gives preference to sources of radicals having a low decomposition point, below 82 ° C (180 ° F) and, in column 4, lines 69-71, US Patent No. 3,849,148 provides a method of finishing glass fibers with an aqueous finish containing a coupling agent, a heat-stable organic peroxide, a nonionic surfactant and a lubricant. This process has successfully given a certain storage capacity to the primed fibers, but has not given results for long-term storage and, on the other hand, the possibility of degradation at high temperature remains.

US Patent No. 3,882,068 discloses a primer composition for glass fibers in several plastic resin systems, in which there is a coupling agent and an emulsion of polyolefins.

US Patent No. 3437550 discloses a method of strengthening the bond between glass fibers and polyolefins by treating the fiber with a crystalline polypropylene matrix. The modifiers of choice for the publication are maleic anhydride and acrylic acid.

U.S. Patent No. 3,883,333 discloses a method and apparatus for making a continuous mat of primed glass fibers which are capable of being bonded to polyolefins. The process and the apparatus, although being continuous, require that the fibers be stored immediately after their formation.

While the above methods and compositions are useful, the need to find a finish remains, a finish which increases the binding of polyolefins to glass fibers. In addition, there remains the need to find a primer for glass fibers which will allow the manufacture of materials composed of primed glass fibers which can be kept indefinitely before their use.

Effective primers that contain peroxides have a limited shelf life and are very sensitive to high temperatures during the drying and storage of fibers, which can cause premature degradation of the peroxides, thereby reducing the effectiveness of the primer. bond the glass fibers to the polypropylene matrix.

The aim of this invention is to overcome the disadvantages presented by the previous methods and compositions, by virtue of a bonding finish between the polyolefin and the continuous glass fibers which is stable during storage and which is not degraded by heat during drying.

These objects of the invention are achieved by the application of a primer formed of a coupling agent, a stabilizer, a lubricant, a non-crosslinked film-forming polymer and a polymer-forming crosslinked film on fiberglass.

The primed wire is wound into a coil for later use in the reinforcement of polypropylene products.

A preferred winding of this invention is obtained by means of an aqueous primer formed from a coupling agent, γ-aminopropyltriethoxysilane, from a stabilizer consisting of cisbutenedioic acid, from a lubricant which is an emulsion of amorphous polypropylene. maleic, an uncrosslinked film-forming agent which is a vinyl acetate homomolymer and a spontaneously reacting vinyl acetate and N-methylolacrylamide copolymer which is applied to the glass fiber of so that it permeates the yarn and increases its ability to strengthen polypropylene articles. The yarn, after having been wound up in an assembly and dried to remove the aqueous support, can be unwound from the assembly and woven into a carpet which is brought into contact with a polypropylene sheet; then, under the action of heat and pressure, an article reinforced with fibers is made.

The use of the sizing system of this invention offers many advantages over the previous methods. The use of a primer which is stable during storage, without limitation of duration, increases the production capacities because it allows the storage and the distribution of windings, of primed glass fibers. Before this invention, it was necessary to use the primed fiber shortly after or immediately after the formation of the carpet used for making composite articles. In addition, the drying of the primed fiber was difficult because the temperature was limited so as not to decompose the peroxides, important elements of the priming. By using this system, it is possible to make windings formed of primed glass fibers in a central location. These can then be sent, without limitation of temperature and atmosphere during transport, to distant points where they will be converted into polyolefin articles reinforced with glass fibers. This represents a considerable improvement in that the manufacture of the glass fiber yarn no longer needs to be carried out in the same place as the articles of polyolefins reinforced with glass fibers. It can therefore be seen that, although the ingredients have been used in other finishes, the combination presented achieves many advantages which are absent from the previous systems.

Any glass suitable for fiber reinforcement and drawing can be processed according to this invention. Lime-potassium glasses and type E borosilicates are particularly suitable for these processes.

The glass fiber of the winding according to this invention can be produced according to the teachings of US Patent No. 2133238. The glass fiber yarns are composed of a multitude of fine glass filaments which are drawn at high speed from cones of molten glass located at the entrance of small holes in a sleeve. During the formation, the filaments are covered with the aqueous primer prepared according to the description below. The coating of the filaments occurs while they are moving at a speed of the order of 305 to 6000 m / min (1000 to 20000 ft / min). The coating occurs in the immediate vicinity of the hot sleeve and the furnace in which the glass is melted, the glass fiber yarn moving little until it is picked up. After the wires have been primed, they can be dried to remove the residual moisture that remains on the wires. The aqueous finish which impregnates and covers the glass fiber yarn is composed of a coupling agent, a stabilizer, a lubricant, a non-crosslinked film-forming agent and a film-forming agent. crosslinked by spontaneous reaction. The coupling agent can be any adhesive compound at the interface, which is used to bond the glass fibers to the polyolefin polymer. Among the typical coupling agents used to join glass fiber yarn and polymers are the metal salts of strong metal acids such as basic chromium chloride and basic chromium sulfide, which have a chosen trivalent metal ion. in the group of the following metals: chromium, cobalt, nickel, copper and lead, and which have at least one hydroxyl group bonded to the metal and at least one anion coming from a strong mineral acid, bonded to the metal; Werner-type complexes in which there is a central trivalent metal atom, such as chromium, which is linked by coordination to an organic acid such as methacrylic acid, for example the chromic chloride complex of methacrylic acid and d '' other Werner-type coupling agents containing vinyl, alkyl,

amine, epoxy, mercapto, thioalkyl and phenol. Coupling agents belonging to the group of silanes and siloxanes are suitable for this invention.

Typical examples of these coupling agents are compounds of hydrolysable silanes or which contain vinyl, allyl, ß-chloropropyl, phenyl, thioalkyl, thioalkaryl, aminoalkyl, methacrylate, epoxy and mercapto groups, and their hydrolysis products, and polymers of hydrolysis products and mixtures of any of them.

A coupling agent of choice is γ-aminopropyltriethoxysilane, and it has been discovered that this product creates an excellent coupling between the glass fiber yarn and the polyolefin polymers, this at low concentration and with good stability.

Any stabilizer can be chosen, if it acts as a secondary coupling agent, to improve the stability of the sizing system, assist in crosslinking, improve the interface between the coupling agent and the fiber, and assist the action of silane during coupling.

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642034

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Typical stabilizers suitable for the primer of this invention are the mono- or dicarboxylic unsaturated ethylenic acids or their anhydrides. Examples of acids or anhydrides include maleic, fumaric, itaconic, citraconic, acrylic, methacrylic, crotonic, isocrotonic, mesaconic, himic, maleic, itaconic and citraconic anhydrides, and mixtures thereof.

A preferred stabilizer is maleic acid (cisbutenedioic acid) which gives a stable system and improves the coupling action of the silane.

Any product which acts as a lubricant in film formation and aids in coupling can be used as a lubricant in this invention. Suitable lubricants are chemically modified propylenes. Maleic or acrylic polypropylenes are preferred because they produce a finished fiber with good storage and further processing properties.

The purpose of the uncrosslinked film-forming polymer in the finishing of this invention is to ensure the integrity of the glass fiber strand during operations. The non-crosslinking polymer provides the finish with the necessary level of plasticity, so that the finished fiber has an extended storage life and also allows a carpet of finished fibers to be woven. In general, the non-crosslinking polymer is a homopolymer or a mixture of homopolymers which do not crosslink under the conditions of finishing and shaping to which the fiber is subjected during the drying of the finishing and during shaping with an olefinic homopolymer such as polypropylene. Typical polymers which form uncrosslinked films and which are suitable for this invention include epoxides, polyesters, polyurethanes and acrylics. A product forming a non-crosslinked film preferably chosen is the homopoly-mother of vinyl acetate, because it is inexpensive, does not degrade in the temperatures used for this formation, and ensures good integrity of the fiber thread. of glass.

The crosslinked film forming polymer can be any polymer or copolymer which contributes to the way, the integrity of the yarn (hardness), the resistance of the film to the finish, the possibility of weaving it, and which is able to crosslink spontaneously.

These spontaneously reacting polymers can be defined as polymers or copolymers capable of crosslinking without external addition under the conditions encountered during the drying of the packet of primed yarn. Typical polymers which react spontaneously upon crosslinking include vinyl acetates, epoxides, polyesters, polyurethanes and acrylic polymers. A polymer of choice is the vinyl acetate / N-methylolacrylamide copolymer which has the advantage of being compatible with polyolefin polymers and particularly polypropylene, of being inexpensive and of being stable at the forming temperature of polyolefins.

The primed glass fibers can be formed, and the primer can be applied according to known methods of formation and application.

A representative method of fiber shaping and lending is described in fig. 2 of U.S. Patent No. 3,849,148 which is incorporated herein by reference. The glass fiber filaments emerge from orifices located on an electrically heated sleeve. These fibers are thinned and, by means of a stretching apparatus, these filaments are harvested to form a glass fiber yarn made of many individual fibers. The finish is applied to the fibers using a traditional mouthpiece or belt applicator. Details on this apparatus can be found in US Patent No. 2728972. The filaments are cooled by air, or better with water, after they come out of the sleeve. The filaments are collected in the form of bundles and are then carried out on a stretching apparatus as described in US Pat. Nos. 329,2013 or No. 3,849,148. The glass fiber thread or threads, if the filaments have been separated several strands at their outlet from the sleeve, are wound in a tube on a mandrel rotating at an approximate speed of 7500 rpm so as to produce a linear displacement of the wire of approximately 3600 to 4600 m / min (12,000 to 15,000 ft / min). The bundled glass fiber yarn is then dried. This is usually done by cooking the fiber assemblies for long enough and at a temperature high enough to remove any residual water. Generally, a treatment lasting 11 hours at 133 ° C (270 ° F) is sufficient in the case of this primer. After drying, the tubes can be removed from their supports, which gives a set of shaped and primed glass fibers. These assemblies can be stored virtually indefinitely after the finishing of this invention. When it is desired to shape a polyolefin composite article from these assemblies, it is arranged so as to be able to pull the yarn and to form a fiber mat as described in US patents Nos. 3883333 or 3664909. The mat is then needled and combined or impregnated with polyolefin resin, or laminated with polyolefin sheets, to form reinforced articles which are heated to a temperature of about 205 to 220 ° C (400 to 430 ° F), under a pressure of '' about 650 kg / cm2 (9250 lb / in.2), for about 5 to 20 min, to bind the glass fibers, prepared according to this invention, to the polyolefin.

Articles made from the glass fiber mat and laminated with polyolefin can be stamped or molded using a variety of methods, including that described by US Patent No. 3,664,909 incorporated herein by reference, to produce laminated polyolefin products which can be used for the manufacture of containers or other articles economically, these having a high resistance in low temperature uses.

The coupling agents can be used in an amount such that good interfacial adhesion between the polyolefin and the glass fibers is obtained. A silane coupling agent, at a concentration of about 0.2 to 18% by weight of the solid parts of the primer, has been recognized as suitable for this purpose.

A preferred percentage of silane-based coupling agent is approximately 6% by weight of the solid parts constituting the primer, so as to give maximum adhesion at minimum cost.

The lubricant can be used in an amount such that good stability of the primer is obtained. It has been found that about 30 to about 80% by weight of the solid parts of the primer is suitable for this purpose. It has been found that a choice amount of maleic amorphous polypropylene of about 60% by weight of the solids constituting the primer is suitable for obtaining good formation and manufacturing characteristics.

The stabilizer can be used in an amount such that a good bond is obtained at the interface between the glass fibers and the film-forming product. It has been found that an amount of 1 to 9% by weight of the solid parts of the primer is suitable for obtaining good training and manufacturing characteristics.

The stabilizer can be used in an amount such that a good bond is obtained at the interface between the glass fibers and the film-forming product. It has been found that 1 to 9% by weight of the solid parts of the primer is suitable for this purpose. It has been found that half the amount of the silane coupling agent gives good adhesion between the film forming agents and the coupling agents. The materials forming a non-crosslinked film and the materials spontaneously forming a crosslinked film are mixed so as to give the desired workability properties to the glass fiber strand. The polymer which does not crosslink is preferably a homopolymer of vinyl acetate which provides the plasticity of the fiber and the use of which depends on the brittle and hardness properties of the spontaneous crosslinked film-forming agent. The spontaneous crosslinked film forming agent ensures the integrity of the glass fiber strand, so that it does not separate into filaments during processing or cutting operations.

A normal concentration range of the polymer which does not crosslink is about 5 to 40% by weight of the solids of the primer. A suitable amount of material spontaneously forming a crosslinked film is about 10 to 50% by weight of the solids forming the primer. A choice quantity of the material spontaneously forming a crosslinking would be approximately 22% by weight of the solids of the emulsion

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primer, so that the fiber has good integrity. A preferred amount of non-crosslinking vinyl acetate homopolymer is approximately 9% by weight of the solids of the primer emulsion to provide optimum workability. Generally, the primer emulsion contains between 80 and 95% water. When using a kiss roll applicator, 83 to 93 parts by weight of water is preferred in the primer solution. So the amount of solids depends greatly on the type of applicator used.

The primed fiber assemblies of this invention can be used to reinforce any article of polymerized resin. However, these fibers find their greatest application in the reinforcement of polyolefin polymers, including polyethylene and polymers of 5-methylpentene. A polyolefin polymer of choice in the application of primed fiber yarn is polypropylene, since this polymer binds very well to the primer described here, is relatively inexpensive and gives good solidity properties when is reinforced with glass fibers. The proportion of polymer relative to glass can be chosen so as to give the finished article the desired properties.

Generally, a ratio of about 10 to 60% by weight of glass is suitable. A preferred proportion of about 35 to 45% by weight of glass in a molded polyproplyene article is chosen so as to balance the costs and the strength properties of the structure.

The amount of primer applied to the glass can be chosen so as to give the finished composite product good structural strength, good fiber integrity and good workability. A suitable amount of primer is about 0.02 to 1% by weight of solid of the primer based on the total weight of the primed glass strand. A range of choice is around 0.6% so as to give good fiber integrity and good handling.

In the following example, which illustrates this invention, the parts and percentages are expressed by weight if not specified otherwise.

Example

Ingredients

Functions

Chemical composition

Parts by weight of the primer

Percent solids in primer

Y-aminopropyltriethoxysilane coupling agent

(Union Carbide A-l 100)

0.7

6

Stabilization cisbutenedioic acid

0.35

3

tor

Lubricant

maleic amorphous polypropylene emulsion 22% active 10% surfactant and KOH 68% surfactant water = alkoxylated phenol.

7.3.

60

Vinyl acetate homopolymer forming agent in emulsion form;

1.1

9

from the film

54% solids (National

not crosslinked

Starch Resyn 25-1031)

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Example (continued)

Ingredients

Functions

Chemical composition

Parts in

Percent

weight of solids

primer primer

Film reti

vinyl acetate emulsion-

2.6

22

culant

N-methylolacrylamide 52%

solid (National Starch

Resyn 25-2828)

Water

87.95

-

The fiberglass primer is prepared by adding most of the deionized water to a tank, then slowly pouring the lubricant with stirring. Next, the coating agent is added. range then maleic acid with continuous stirring. After the addition of the maleic acid, the mixture is stirred for 20 min in order to effect the dissolution of the acid. Then the non-crosslinked film-forming agent is added, followed by the emulsion of the polymer which will crosslink, the latter being diluted with the same amount of cold deionized water before the addition. The additional water is then added and the test is checked to find out whether the specifications are in the pH range of around 6 and the solids composition of around 5%.

The aqueous finish is applied to the filaments of fibers emerging from a 400-hole sleeve. The filaments are treated with a kiss roll applicator to cover with a film of about 0.6% by weight of solid relative to the weight of the glass.

The filaments are gathered into four or more threads, then are wound on cores to form bundles of about 9 kg each or more (20 lb). These assemblies are treated for approximately 11 h at 132 ° C (270 ° F). After this treatment, the packages can be stored indefinitely at room temperature. These assemblies can then be used to make a carpet of continuous fibers which is then needled and laminated with polypropylene in a ratio of 60% by weight of polymer to polypropylene and 40% by weight of carpet. The polyolefin resin and the mat are combined at a temperature of about 250 ° C (400 ° F), at a pressure of about 6.3 kg / cm2 (90 lb / in.2), for about 5 min, to bind the reinforced fibers to the polyolefin. Heating is carried out between stainless steel belts. The laminate of prepared fibers and polypropylene is then molded in the form of test pieces such as those described in columns 6 to 7 of US Pat. No. 3,849,148, and their structural strength is tested. The bending force is at least 1620 kg / cm2 (23,000 lb / in.2) on average, and the flexural modulus is approximately 70 x 10th kg / cm2 (1 x 10 ° lb / in. 2).

This example shows that the glass fiber reinforced propylene primed according to this invention provides sufficiently well reinforced articles, even after a long period of storage.

A pigment or colorant can be added to the primer without interfering with its effects.

A primer application device can be used, which will not require as much water in the primer. In addition, the bundles of fibers can be used for the reinforcement of poly-merized materials other than polyolefins. Likewise, the fibers prepared according to this invention could be combined with other fibers prepared differently, with fibers not prepared or with portions of yarn prepared according to this invention.

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Claims (32)

642,034 2 1. Winding of glass fibers impregnated with a finish consisting of a coupling agent, a stabilizer, a lubricant, a non-crosslinked film forming polymer and a crosslinked film forming polymer. 2. Winding according to claim 1, characterized in that the coupling agent is chosen from the group of silanes and siloxa-nes. 3. Winding according to claim 1, characterized in that the coupling agent is an aminosilane. 4. Winding according to claim 1, characterized in that said stabilizer consists of a mono- or diacid chosen from the group of ethylenically unsaturated carboxylic acids and corresponding anhydrides. 5. Winding according to claim 1, characterized in that the stabilizer contains cisbutenedioic acid. 6. Winding according to claim 1, characterized in that said lubricant contains an emulsion of a chemically modified polypropylene. 7. Winding according to claim 1, characterized in that said primer comprises, by weight, 2 to 18% of coupling agent, 1 to 9% of stabilizer, 30 to 80% of lubricant, 5 to 40% of non-crosslinked film forming agent and 10 to 50% of crosslinked film forming agent. 8. Winding according to claim 1, characterized in that the lubricant comprises maleic amorphous polypropylene. 9. Winding according to claim 1, characterized in that said non-crosslinked film-forming polymer is chosen from the group of epoxypolymers, polyesters, polyurethanes, acrylic polymers and mixtures thereof. 10. Winding according to claim 1, characterized in that said non-crosslinked film-forming polymer is a homopolymer of vinyl acetate. 11. Winding according to claim 1, characterized in that said crosslinked film-forming polymer is chosen from the group of epoxypolymers, polyesters, polyurethanes, acrylic polymers and copolymers, and mixtures thereof. 12. Winding according to claim 1, characterized in that the crosslinked film-forming polymer is a copolymer of vinyl acetate. 13. Winding according to claim 1, characterized in that the primer contains y-aminopropyltriethoxysilane as coupling agent, cisbutenedioic acid as stabilizer, amorphous maleic polypropylene as lubricant, a vinyl acetate homopolymer as polymer non-crosslinked film former and a vinyl acetate / methylolacrylamide copolymer as a crosslinked film former. 14. Winding according to claim 13, characterized in that said finish forms about 0.6% by weight of the primed fibers. 15. Winding according to claim 14, characterized in that said finish contains, by weight, about 6% of said silane, about 3% of said cisbutenedioic acid, about 60% of said maleic amorphous polypropylene, about 9% of said acetate homopolymer vinyl, and about 22 parts of said vinyl acetate / methylolacrylamide copolymer. 16. Winding according to claim 1, characterized in that said stabilizer contains himic anhydride. 17. A method of manufacturing a composite article, characterized by the union of an olefin polymer and primed glass fibers, by the application of pressure; said primed glass fibers being impregnated with a primer composed of a coupling agent, a lubricant, a non-crosslinked polymer and a crosslinked polymer. 18. The method of claim 17, characterized in that said glass fibers are in the form of a sheet. 19. The method of claim 17, characterized in that said polyolefin polymer is selected from the group formed by the po- lyethylene, polypropylene, 5-methylpentene and mixtures thereof. 20. The method of claim 17, characterized in that said glass fibers form 10 to 60% by weight of said article. 21. The method of claim 17, characterized in that said coupling agent is chosen from the group of silanes and siloxanes. 22. Method according to claim 17, characterized in that the coupling agent is an aminosilane. 23. The method of claim 17, characterized in that the stabilizer is composed of a mono- or diacid chosen from the group of ethylenically unsaturated carboxylic acids and the corresponding anhydrides. 24. The method of claim 17, characterized in that said stabilizer is composed of cisbutenedioic acid. 25. The method of claim 17, characterized in that said lubricant consists of an emulsion of a chemically modified polypropylene. 26. The method of claim 17, characterized in that said primer contains, by weight, between 2 and 18% of coupling agent, between 1 and 9% of stabilizer, between 30 and 80% of lubricant, between 5 and 40 parts of non-crosslinked film forming agent and 10 and 50 parts of crosslinked film forming agent. 27. The method of claim 17, characterized in that said lubricant comprises amorphous amorphous polypropylene. 28. The method of claim 17, characterized in that said non-crosslinked film-forming polymer is a member of the group consisting of epoxypolymers, polyesters, acrylic polymers and copolymers, and mixtures thereof. 29. Method according to claim 17, characterized in that the said non-crosslinked film-forming polymer is a homopolymer of vinyl acetate. 30. The method of claim 17, characterized in that said crosslinked film-forming polymer is chosen from the group formed by epoxypolymers, polyesters, acrylic polymers and copolymers, and mixtures thereof. 31. Method according to claim 17, characterized in that ■ said crosslinked film-forming polymer is a copolymer of vinyl acetate. 32. Composite article obtained in accordance with the method according to one of claims 17 to 31.