EP2091885A1

EP2091885A1 - Sized glass filaments intended for reinforcing polymeric materials, more particularly by moulding

Info

Publication number: EP2091885A1
Application number: EP07731884A
Authority: EP
Inventors: Dino Lombino; François ROEDERER; Claire Metra
Original assignee: OCV Intellectual Capital LLC
Current assignee: Owens Corning Intellectual Capital LLC
Priority date: 2006-04-12
Filing date: 2007-04-06
Publication date: 2009-08-26
Also published as: KR20090008322A; RU2458873C2; FR2899893A1; FR2899893B1; MX2008013060A; CN101460420A; RU2008140363A; US20100022698A1; CA2647974A1; BRPI0711543A2; WO2007116191A1; JP2009533307A

Abstract

The invention relates to glass filaments which are intended for reinforcing polymeric materials and which are coated with a sizing composition comprising, as adhesive film-forming agents, a mixture of at least one polyvinyl acetate and at least one polyvinylpyrrolidone, said at least one polyvinyl acetate representing 70% to 90% by weight of the solids of the size. The resulting glass filaments are used as reinforcements in the production of mouldings having a thermosetting matrix that are obtained by simultaneous spraying of said filaments and resin, in particular by LFI (Long Fibre Injection) moulding.

Description

ENSIMES GLASS YARNS FOR REINFORCING POLYMERIC MATERIALS, IN PARTICULAR BY MOLDING.

The invention relates to glass son coated with a sizing composition for reinforcing organic materials of the polymer type, the sizing composition used to coat said son and the composites thus obtained, in particular by molding.

The glass threads used for reinforcement in general are industrially produced from molten glass threads flowing from the multiple orifices of a die. These nets are drawn mechanically in the form of continuous filaments, and are then combined into base wires which are then collected, for example by winding on a rotating support. Before their assembly, the filaments are coated with a sizing composition by passing on a suitable device such as coating rolls. The sizing composition proves essential for several reasons.

During the manufacture of reinforcing son, the sizing composition protects the glass filaments from the abrasion that occurs when they rub at high speed on the various organs used to guide and collect them. It also establishes bonds between the filaments which makes it possible to give cohesion to the thread. As the yarn is made more upright, its handling, especially during weaving operations, is improved and untimely breaks are avoided.

During the manufacture of composite materials, the sizing composition promotes the wetting and impregnation of the glass son by the matrix to be reinforced, which matrix is generally implemented in the form of a more or less fluid resin. The mechanical properties of the final composite are therefore significantly improved.

The materials to be reinforced can integrate the glass threads in different forms: continuous or cut threads, mats of continuous or cut threads, fabrics, ...

Composites that incorporate cut glass yarns can be obtained, inter alia, by the technique of "simultaneous projection molding" which consists in projecting inside a mold a resin to be reinforced and glass threads of variable length. . The threads and the resin are projected together on the inner walls of the mold by means of a "gun" comprising an incorporated cutter capable of cutting the son extracted from one or more windings and a device for spraying the resin. This process, simple and flexible, is particularly suitable for the production of single or small series of parts based on thermosetting polymers belonging to the family of polyesters or epoxies.

A particular technique for the manufacture of composites by simultaneous projection molding is known under the name "Long Fiber Injection" (LFI). It consists in simultaneously projecting into a mold wires cut at a high speed (of the order of 300 to 1200 meters per minute) in cycles lasting a few tens of seconds and reactive monomers capable of giving a resin by polymerization , and then apply a counter-mold. This technique is particularly suitable for the production of polyurethane parts, especially for the automobile, for example interior door trim, rear shelves, dashboards and flags.

The quality of the composites obtained by these processes largely depends on the properties provided by the glass strands, and therefore on the size which coats them and the conditions of use. In particular, it seeks sizing compositions for obtaining a wire that can be extracted from a winding, for example a cake or a roving ("roving" in English), forming the least possible loop and retaining its integrity after cutting.

The formation of loops is not desired for the following reasons: in the first place, the loops impede the passage of the wire inside the flexible arm which serves to cut and project said wire into the mold. It follows a malfunction of the cutter that does not deliver a constant amount of cut glass in the mold,

- Then, the strong stress of the wire at the start of each cutting cycle causes the "filamentization" of the wire at the loops, ie a rupture of the filaments constituting the wire and the joint production of "wad" which s accumulates in various parts of the process. In detaching from the cutter, the flock forms clusters in the resin which adversely affect the quality of the molded part. In either case, the production is diminished because of the stops necessary to clean the soiled organs.

It is also desired that the integrity of the wire remains at a high level so that it does not "open" by separating the filaments that constitute it during the start of each cutting cycle where the tension on the wire is important.

But it is also necessary that the filaments remain bound after cutting so that the cut wire can fulfill its role of reinforcement of the matrix in the final piece.

The improvement of these properties should not be to the detriment of other properties. In particular, it is important for the wire to have "slippery" so that it can be unrolled or unwound easily from the winding without significant tension that could damage the wire, while having sufficient stiffness to allow it to be cut in good conditions.

It is also necessary that the cut wire can be rapidly impregnated with the precursor monomers of the resin and that the mixture obtained be homogeneous and be distributed uniformly in the mold, without "collapsing" by gravity.

Measured glass wires adapted to these projection molding techniques are already known.

In EP-A-0 869 927 there are described glass threads coated with a sizing composition comprising, as sticky film-forming agents, the combination of at least one low molecular weight polyvinyl acetate A and at least one vinyl acetate copolymer B self-crosslinkable thermally in a weight ratio A / B greater than or equal to 1. These son have a high rate of impregnation with the resin.

In WO-A-02/059055, the glass strands are coated with a substantially aqueous size composition which comprises at least one bis-silane A and at least one unsaturated monosilane (B) selected from vinylsilanes and methyl ( acrylosilanes). Sizing increases the life of the cutter blades. The speed of impregnation of the threads is important.

In FR-A-2,279,688, the glass strands are coated with a lubricant comprising an aqueous mixture based on polyvinyl acetate, a fatty acid lubricant, methacrylato chromic chloride and gamma (ethylene diamine) propyltrimethoxysilane. If the performance level of these wires is generally satisfactory, the number of loops per unit length of wire remains high and the integrity is insufficient.

The object of the present invention is to propose a glass reinforcement yarn, in particular intended for simultaneous projection molding, in particular for LFI molding, which forms few loops when it is extracted from the winding and which has a better integrity than the known son adapted to this type of molding.

The invention relates to a glass wire coated with an aqueous sizing composition which comprises, as sticky film-forming agents, the mixture of at least one polyvinyl acetate and at least one polyvinylpyrrolidone.

In the present invention, "glass threads coated with a sizing composition which comprises ..." means not only glass threads coated with the composition in question as obtained at the immediate exit of the composition. organ or sizing organs, but also these same son after they have undergone one or more other treatments. By way of example, mention may be made of the drying operations intended to eliminate the liquid phase of the composition, and the treatments leading to the polymerization / crosslinking of certain constituents of the sizing composition.

Still in the context of the invention, "son" means the basic son from the gathering under the die of a multitude of filaments, and products derived from these son, including the assemblies of these basic son in rovings. Such assemblies can be obtained by unwinding simultaneously several windings of basic son, and then gathering them in locks which are wound on a rotating support. It may also be "direct" rovings of a linear density (or linear density) equivalent to that of assembled rovings, obtained by the gathering of filaments directly under the die and the winding on a rotating support. According to the invention, the term "aqueous sizing composition" means a sizing composition in the form of a solution in which the liquid phase consists of 97% by weight of water, preferably 99% and better still 100%, the complement being constituted if necessary of one or more essentially organic solvents which can help solubilize certain constituents of the sizing composition. In general, the sizing composition contains 85 to 95% by weight of water, preferably 89 to 94%.

According to the invention, the sizing composition comprises, as sticky film-forming agents, the mixture of at least one polyvinyl acetate and at least one polyvinylpyrrolidone.

Polyvinyl acetate is important to quickly reach a high level of impregnation of the son by the resin and get a good conformability of the son / resin mixture in the mold. Polyvinyl acetate also brings stiffness to the wire.

The molecular weight of the polyvinyl acetate is generally less than or equal to 80,000 g / mol, preferably less than or equal to 70,000 g / mol and preferably is between 29,000 and 65,000 g / mol. The amount of polyvinyl acetate is generally 70 to 90% by weight of the solids of the size deposited on the wire, preferably 75 to 85%.

The polyvinylpyrrolidone participates in bonding the glass filaments, thereby increasing the integrity of the yarn after cutting, and furthermore makes it possible to adjust the tackiness of the yarn and to reduce the ability of the yarn to form loops.

The molecular weight of the polyvinylpyrrolidone is generally less than or equal to 4000 g / mol, preferably less than or equal to 3000 g / mol, and advantageously between 1000 and 2000 g / mol.

In the size, the amount of polyvinylpyrrolidone is such that the weight ratio polyvinyl acetate / polyvinylpyrrolidone varies from 14 to 900, preferably 18.75 to 106.25. In addition to the aforementioned components which essentially participate in the structure of the size, the sizing composition may comprise one or more other components (hereinafter referred to as "additives").

The sizing composition may thus comprise at least one plasticizing agent whose function is to soften the polymer chains of the film-forming film-forming agents. By contributing to lowering the glass transition temperature of the tackifiers, the plasticizer makes it possible to obtain a better "conformability" of the cut son / resin mixture in a mold of complex shape. In general, the plasticizing agent is chosen from glycols derivatives such as alkylene glycol dibenzoates, preferably dibenzoates of ethylene and / or propylene glycol.

The amount of plasticizer in the size depends on the degree of flexibility that it is desired to give the wire, it being understood that the wire must be rigid enough to allow it to distribute itself properly within the resin. Generally, the plasticizer is 6 to 20% by weight of the solids of the size.

The composition may further comprise at least one lubricating agent in an amount of 3 to 9% by weight of the solids of the sizing composition. In addition to the role of protecting the filaments against mechanical abrasion, the lubricant helps to limit the formation of flock and to avoid the gluing of the turns on the windings of basic threads.

In general, these agents are chosen from polyalkylene imide type cationic compounds and poly (oxyalkylene) poly (alkylene glycol) fatty acid esters and ionic compounds, such as polyethylene glycol monolaurate, or acid amide type. fatty and poly (oxyalkylene) such as hydrogenated tallow amides and polyethylene.

The sizing composition may also comprise at least one coupling agent for hanging the size on the surface of the glass filaments. The coupling agent is generally chosen from silanes such as gamma-glycidoxypropyltrimethoxysilane, gamma-acryloxypropyltrimethoxysilane, gamma-methacryloxypropyltrimethoxysilane, poly (oxyethylene / oxypropylene) -trimethoxysilane, gamma-aminopropyltriethoxysilane, vinyltrimethoxysilane, phenylaminopropyltrimethoxysilane or styrylaminoethylaminopropyltrimethoxysilane, siloxanes, titanates, zirconates and mixtures of these compounds.

Preferably, the silanes are selected.

The amount of coupling agent generally represents less than 7% by weight of the solids of the sizing composition, preferably is greater than 2% and most often is of the order of 5%.

The size may further comprise at least one antistatic agent which contributes to improving the cutting ability of the glass yarn. The antistatic agent is selected from metal salts such as lithium chloride. The amount antistatic agent generally represents at most 5% of the weight of the solids of the size.

All these additives combine to obtain reinforcement yarns that can be easily manufactured, which can be extracted without difficulty from the windings with a reduced number of loops and which can be cut without any problem and projected into a mold while retaining a good integrity.

The yarn according to the invention may undergo an additional step of coating it with an additional size ("over-image") in order to give it a better slipperiness and to reduce the level of electrostatic charges in order to give the yarn a better aptitude. the cutting. The application of a super-image is advantageous in the case where the sizing composition contains no anti-static agent. The oversteaming then comprises as antistatic agent at least one quaternary ammonium salt. In general, the amount of overstocking is 0.02 to 0.2% of the weight of the yarn, preferably 0.05 to 0.10%.

The glass wire coated with the sizing composition according to the invention has a loss on ignition of less than 3%, preferably less than or equal to 2%. Advantageously, the loss on ignition is greater than 1, 25% and better still is between 1, 3 and 1, 7%. Most often, the son of glass according to the invention are in the form of son son windings which is subjected to a heat treatment. This treatment is intended essentially to eliminate the water provided by the sizing composition and, where appropriate, to accelerate the crosslinking of film-forming agents. The conditions of the treatment may vary according to the mass of the winding. In general, the drying is carried out at a temperature of the order of 110 to 140 ^° C. for several hours, preferably 12 to 18 hours.

The son coated with the sizing composition according to the invention may be made of glass of any kind as long as it is suitable for being fiber, for example E, C, AR (alkali-resistant) glass, or at a low temperature. boron level (less than 5%).

These same son consist of filaments whose diameter may vary to a large extent, for example 10 to 20 microns, preferably 11 to 16 microns. Advantageously, these threads have a titer of between 30 and 200 tex, preferably 50 and 160 tex.

Another subject of the invention relates to the aqueous sizing composition suitable for coating said glass yarns, which composition is characterized in that it comprises the constituents below, in the following weight contents expressed in percentages of the solids. :

- 70 to 90% of at least one polyvinyl acetate, preferably 75 to 85%

0.1 to 5% of at least one polyvinylpyrrolidone, preferably 0.8 to 4%

- 6 to 20% of at least one plasticizer, preferably 7 to 15% - 3 to 9% of at least one lubricating agent, preferably 3.5 to 6.5%

2 to 7% of at least one coupling agent, preferably 3.5 to 6%

- 0 to 5% of at least one anti-static agent.

Preferably, the sizing composition comprises between 5 and 15% by weight of solids, preferably between 6 and 14% and more preferably between 8 and 12%.

The sizing composition is prepared by simple mixing of the above constituents and water. When the coupling agent is a silane, it is subjected to a step of prior hydrolysis in the presence of an acid.

Another object of the invention relates to composites comprising glass son coated with the sizing composition. Such composites comprise at least one thermosetting material, preferably a polyester, a vinylester, an acrylic polymer, a polyurethane, a phenolic or epoxy resin, and glass threads consisting, in whole or in part, of glass yarns in accordance with the invention. 'invention. The level of glass within the composite is generally between

20 and 45% by weight, and preferably between 25 and 35%.

The invention also relates to the use of glass son coated with the sizing composition for the production of composite parts by the technique of simultaneous projection molding, in particular by the technique LFI.

The following example illustrates the invention without limiting it. The properties relating to the glass strands coated with the sizing composition are measured as follows: - the loss on ignition, in percentage, of the sized glass wire is measured under the conditions of the ISO 1887 standard.

- The number of loops is measured by unwinding the wire from a roving over a length of 500 meters, and scrolling between two optical sensors that detect defects. The number of loops is given per kg of wire.

- The flock is measured by passing 0.5 kg of wire unwound from a roving on a docking, at a speed of 80 m / min, and determining the mass of fibrils generated during scrolling. The flock is given in mg / kg of yarn.

the half-discharge time (in seconds) is calculated from the measurements of the electric field obtained by means of a static voltmeter, on the wire placed in a static enclosure at 20 ^° C. and 20% relative humidity. - the integrity of the yarn is measured by unrolling the yarn in a cutter

WOLFANGEL at the speed of 1200 m / min, without making the cut, and observing the appearance of the wire according to the scale of value ranging from 1 = bad, non-integral wire, the individualized base wires to 5 = very good , wire integrates. - the integrity of the wire after the cut is measured in the following manner: the wire unwound from a roving is introduced into a cutter WOLFANGEL 500 which cuts it and projects it substantially horizontally on a vertical wall (speed of cutting: 1200 m / min, length: 12 mm). The integrity of the cut wire is assessed visually according to the following scale of values: 1 = bad, cottony appearance; 3 = medium, aspect

"Hair"; 5 = very good, no splitting of the wire. EXAMPLE

A sizing composition is prepared in the form of an aqueous solution comprising, as a weight percentage of solids: ^» film-forming film-forming agents

- polyvinyl acetate; molecular weight: 50000 ⁽¹⁾ polyvinylpyrrolidone; molecular weight: 1200-2000 ⁽²⁾ 3.75

• coupling agents

gamma-methacryloxypropyltriethoxysilane ⁽³⁾ 1 aminosilane ⁽⁴⁾ 4

^" Plasticizing agent

- mixture of diethylene glycol dibenzoate and dibenzoate 7.45 of dipropylene glycol (50:50 weight ratio) ⁽⁵⁾ - lubricating agents

- polyethylene imide with free amide functions ^(6> 3.8

• water: enough to give 100 ml of sizing composition

The preparation of the sizing composition is carried out as follows: The methoxy groups of the silanes ^{(3) (4) are} hydrolysed by addition of acid to an aqueous solution of this silane maintained with stirring. The other constituents are then introduced, still with stirring, and the pH is adjusted to a value of 4 ± 0.2, if necessary.

The weight content of solids in the sizing composition is equal to 9.9%.

The sizing composition is used to coat, in known manner, glass filaments E about 12 μm in diameter drawn from glass threads flowing from the orifices of a die, the filaments then being collected in the form of of basewires of title equal to 57 tex. The coil is then dried at 130 ° C for 12 hours.

The base yarns extracted from 6 windings are brought together to form a roving.

The wire thus obtained has a loss on ignition equal to 1, 4%.

In Table 1 below are collected the results of the measurements made on the yarn according to the invention, noted Example, and on a thread adapted to the molding technique LFI (sold by OWENS CORNING under the reference ME1020) coated with a sizing polyvinyl acetate, noted

Reference. TABLE 1

It can be seen from Table 1 that the yarn of the example according to the invention has better performances than the reference yarn with equivalent quantity of flock and half-discharge time, namely that it has a number of loops. lower and better integrity before and after cutting.

(1) marketed under the reference "Rhodopas ^® V1865" by RHODIA; solids content: 54%

(2) marketed under the reference "Luviskol ^® K90" by BASF; solids content: 20%

(3) marketed under the reference "Silquest ^® A-174" by GESM; solids content: 70%

(4) marketed under the reference "Silquest ^® A-1128" by GESM; solids content: 50%

(5) marketed under the reference "K-Flex ^® 500" by NOVEON; solid content: 100%

(6) Sold under the "Emery ^® 6717" reference by Cognis; solid content: 100%

Claims

Glass thread coated with an aqueous sizing composition, characterized in that said sizing composition comprises, as sticky film-forming agents, a mixture of at least one polyvinyl acetate and at least one polyvinylpyrrolidone and in that said at least polyvinyl acetate represents 70 to 90% by weight of the solids of the size.

2. The glass yarn according to claim 1, characterized in that said at least polyvinyl acetate preferably represents 75 to 85% of the solids of the size.

3. Glass yarn according to claim 1 or 2, characterized in that the weight ratio polyvinyl acetate / polyvinylpyrrolidone varies from 14 to 900, preferably 18.75 to 106.25.

4. Glass yarn according to one of claims 1 to 3, characterized in that the polyvinyl acetate has a molecular weight less than 80000 g / mol, preferably less than 70000 g / mol and preferably between 29000 and 65000 g / mol.

5. Glass yarn according to one of claims 1 to 4, characterized in that the polyvinylpyrrolidone has a molecular weight less than or equal to 4000 g / mol, preferably less than or equal to 3000 g / mol and preferably between 1000 and 2000 g / mol.

6. The glass strand according to one of claims 1 to 5, characterized in that it has a loss on ignition less than 3%, preferably less than or equal to 2%. 7. Glass strand according to claim 6, characterized in that it has a loss on ignition greater than 1, 25%, preferably between 1, 3 and 1,

7%.

8. The glass yarn according to one of claims 1 to 7, characterized in that the sizing composition further comprises at least one plasticizer selected from glycols derivatives such as alkylene glycol dibenzoates.

9. The glass yarn according to claim 8, characterized in that the plasticizer is an ethylene dibenzoate and / or propylene glycol.

10. The glass yarn according to one of claims 1 to 9, characterized in that the sizing composition further comprises at least one lubricating agent selected from cationic compounds of the polyalkylene imide type, and the ionic compounds of the type d esters. fatty acids and poly (alkylene glycols) poly (oxyalkylene) or amide type of fatty acids and poly (oxyalkylene).

11. Glass yarn according to claim 10, characterized in that the lubricating agent is a polyethylene glycol monolaurate or a hydrogenated tallow amide and polyethylene.

12. Glass yarn according to one of claims 1 to 11, characterized in that the sizing composition further comprises at least one coupling agent selected from silanes, siloxanes, titanates, zirconates and mixtures of these compounds.

13. An aqueous sizing composition for coating a glass yarn according to one of claims 1 to 12, characterized in that it comprises the constituents below, in the following weight contents expressed as percentages of solids:

- 70 to 90% of at least one polyvinyl acetate, preferably 75 to 85%

0.1 to 5% of at least one polyvinylpyrrolidone, preferably 0.8 to 4%

2 to 7% of at least one coupling agent, preferably 3.5 to 6%

- 0 to 5% of at least one anti-static agent.

14. Sizing composition according to claim 13, characterized in that it comprises between 5 and 15% by weight of solids, preferably between 6 and 14% and more preferably between 8 and 12%.

15. Composite comprising at least one thermosetting polymer material and reinforcing glass son, characterized in that all or part of the glass son consists of son according to one of claims 1 to 12.

16. Composite according to claim 15, characterized in that the thermosetting material is a polyester, a vinylester, an acrylic polymer, a polyurethane, a phenolic resin or epoxy.

17. Composite according to claim 15 or 16, characterized in that it has a glass content of between 20 and 45% by weight, preferably between 25 and 35%.

18. Use of glass son according to one of claims 1 to 12 for the production of composites by the technique of simultaneous projection molding, in particular by the technique LFI.