ES2248278T3 - GLASS AND BITUMINOUS MEMBRANE VELO THAT UNDERSTANDS THE VEIL AS SUBSTRATE. - Google Patents

Abstract

Veil based on usable fibers for the constitution of bituminous membranes, comprising glass fibers, organic fibers and a binder, obtained from an aqueous suspension of cut glass and organic fibers, characterized in that the organic fibers have a contraction rate , at a temperature of 130 ° C produced in a humid or steam atmosphere for 30 minutes, less than or equal to 5%.

Description

Glass veil and bituminous membrane that It comprises the veil as a substrate.

The present invention relates to the field of fiber-based sheet materials and refers more particularly to a glass veil that can be used as a substrate for the realization of products coated or impregnated with bitumen, especially for cover and / or sealing applications.

In the field of cover or tightness, it is known to use bituminous membranes that are applied on the surface to cover or to waterproof. These membranes are constituted, for example, with a sheet-shaped substrate coated or impregnated with a bituminous matrix.

The sheet-shaped materials can be of diverse natures and usually obtained from fibers organic or mineral, and preferably not tissues.

Among the usable materials, the veils of Glass are of great interest, as they guarantee stability dimensional, over time, of the bituminous membrane.

Glass veils can be obtained by any known technique itself, in particular the known technique as a wet track, especially described in the reference work The Manufacturing Technology of Continuous Glass Fibres, K. L. LOEWENSTEIN, Ed. ELSEVIER, 2nd edition, 1983, pp. 315-317. This technique, which resembles the techniques litter bins, consists of preparing an aqueous suspension of fibers of cut glass, deposit this suspension in a film on a Suction filter pad to remove part of the water of the deposited film, apply a binder composition on the wet film, dry the veil and crosslink the binder on a stove and then condition the veil as desired. The final product is presented in the form of a fairly thin sheet (thickness of the order of 0.2 to 0.8 mm), generally conditioned in roll form.

The binder is often a aqueous composition based on urea-formaldehyde resin, presenting this resin a satisfactory thermal stability at temperatures of the subsequent use of the impregnating bitumen.

The glass veils present, however, the inconvenience of a relatively low resistance to tearing, which penalizes the comfort of use and constrains especially the user to take precautions in the case of manipulation to constitute the membrane or place it on the roof.

To remedy this problem, there are complex substrates that associate a veil based on organic fibers that have a good tear resistance and a grid of glass that confers dimensional stability to the whole. These complexes that associate two intermediate products are, however, of a complicated manufacturing.

The object of the invention is to propose a glass-based material whose tear resistance is improved without that its manufacture is more complicated than that of a veil traditional.

The document EP-A-0763 505 describes a mat of fiberglass for the manufacture of roofing squeals bituminous, whose resistance is improved thanks to a binder of urea-formol enhanced with a vinyl additive self-crosslinkable. In this mat, a smaller proportion of fibers may not be made of glass, and be chosen especially among organic fibers such as Nylon®, polyester, polyethylene, and polypropylene. This document does not give an indication precise about these organic fibers, and does not contain any examples particular that illustrates this possibility.

The present invention is based on the discovery that numerous organic fibers do not lend themselves conveniently to the manufacture of a veil and even have a very negative effect on the properties of the veil in the application of bituminous covers, but that a very precise selection of Synthetic materials can solve this problem.

In this regard, the invention aims at a fiber-based veil usable for the constitution of membranes bituminous, comprising glass fibers and organic fibers joined by a binder, characterized in that the fibers have a contraction rate at 130 ° C less than or equal to 5%, in atmosphere of steam or wet for 30 minutes.

It is required that the expression "glass veil" encompasses, according to the invention, materials well known for the man of the trade, fiberglass based products. It is about of thin sheet-shaped materials, essentially structure isotropic, that is to say that there is no preferential orientation of the fibers In practice, a veil can be qualified by means of "isotropy relationship"

\ frac {\ text {Resistance to machine-tension veil}} {\ text {Resistance to veil traction in the direction cross}}

which is generally of the order of 1 and especially of the order of 1 to 1.5, which sometimes reaches 2. This essentially random orientation of the fibers is obtains, generally, from the presentation of the fibers in cut threads for the manufacture of the veil, for example according to the wet technique mentioned more above.

The choice of organic fibers according to the above criteria gives the veil a good quality and, in in particular, mechanical and thermal resistance compatible with the subsequent application of impregnation with bitumen, while the other fibers give the veil a thermal and / or mechanical resistance insufficient.

First, the organic fibers used in veil manufacturing they have a high melting point for avoid degradation in all thermal stages of the veil manufacturing, especially drying and cross-linking in the stove, and of the application of the veil, in particular upon contact with the bituminous binder. In general, organic matter synthetic is chosen to have a melting point higher than approximately 220 ° C.

According to the invention, the fibers are selected based on their percentage of thermal contraction; is magnitude corresponds to the dimensional variation, in this case a fiber contraction after it has been exposed to a given temperature for a defined time. For this, the initial length Li of the fiber, before heating, and then the final length Lf, the contraction percentage being equal to:

\hskip2cm

(en tanto por ciento)R = (Li - Lf) / Li,

 \ hskip2cm 

(in percent)

The determinant contraction percentages of according to the invention they are expressed for a temperature of 130 ° C produced in a water vapor atmosphere for a period of 30 min.

According to the invention, the contraction is choose less than or equal to 5%, preferably 4%, in particular 3% and, for example of the order of 2 to 3%.

Advantageously, this fiber quality can be obtain from polymeric materials semi-crystalline, particularly when the spinning procedure allows a stretch that increases the percentage of crystallinity. Other manufacturing conditions such as the presence of nucleating agents or the factor temperature can also lead to the organization of base macromolecules so that the initial structure polymer amorphous, begin to adopt a crystalline structure and become semi-crystalline.

The fibers that respond to the demands of the invention can be found among polyester fibers, especially poly (alkylene terephthalate), and in particular poly (ethylene terephthalate).

Organic fibers adapted to the nonwoven manufacturing processes wet, containing a sizing that allows the dispersion in water of the filaments individual.

Organic fibers can have dimensions variables, with an average diameter of the order of 7 to 25 µm, for a title of the order of 0.5 to 2 dtex. The fibers are cut with a length of the order of one or several tens of millimeters, and especially from 6 to 30.

The effect of organic fibers is very perceivable from 5% by weight with respect to the total weight of fibers The proportion of organic fibers is advantageously of order of 5 to 30%, especially 20 to 30%, and in particular of approximately 25%, by weight with respect to the total weight of fibers

The glass fibers used in accordance with the invention are of a conventional type for the realization of veil, in the form of cut threads, with a length of the order of ten of millimeters, and especially 6 to 30 mm, preferably of approximately 10 to 20 mm, and for example 12 to 18 mm. Be comprises that a certain proportion of threads (for example 5 to 10%) They can be cut with a length of up to 100 mm. On the other hand, it you can insert continuous thread into the veil, especially glass, as reinforcement in the longitudinal direction.

The binder used to constitute the veil It is advantageously based on urea-formaldehyde resin, preferably modified with vinyl and / or acrylic additives, of the known way especially of documents US-A-681 802, and EP-A-0 763 505. The proportion of binder is generally 15 to 30%, by weight of dry matter With respect to the veil.

The veil is manufactured with a usual weight for the glass veils, of the order of 30 to 150 g / m2, and in particular 50 to 120 g / cm2.

Taking into account the density difference between glass and organic fibers, the amount of matter in the veil according to the invention for a given weight, is a bit higher than that contained in a glass veil, which translates into a relatively higher thickness and / or a lower porosity. The porosity is, for example of the order of 1,500 to 1,900 L / m2, for a veil of 50 g / m2.

The veil according to the invention, being particularly adapted to sealing applications and / or cover, the invention also has a membrane bituminous comprising a spread, coated or impregnated substrate with a bituminous matter, characterized in that the substrate is a Veil as described above.

The bituminous matrix can be chosen among the matrices known per se: natural bitumen, modified or not, or synthetic binder, such as "clear binder" that especially allows to give the membrane a decorative color.

The following examples, given by way of title, are not limiting, illustrate the invention.

Example 1

An aqueous fiber suspension is prepared in the that the fibers comprise:

-

75%, by weight of cut glass E, which has a filament diameter of 10 µm and a linear mass of 360 tex, the length being 12 mm cut,

-

25% by weight of cut polyester thread, available from the company KURARAY, with reference EP 133, adapted to the procedures papermakers, and capable of being dispersed in water. This thread is characterized by a filament diameter of 12 µm and a mass linear of 14 dtex, being the length of cut of 15 mm. It is about of a thread of poly (ethylene terephthalate) stretched to increase its crystallinity, which has a contraction rate of order of 2% at 130 ° C in humid medium for 30 minutes of exposure, and a contraction rate of 3% at 170 ° C in a dry atmosphere for 15 minutes of exposure

The fiber suspension that also contains the usual additives, namely anti-foam, dispersant, viscosity agent, is used under conditions standard in a veil manufacturing machine comprising:

(i)

a hydroconformer on which a wet film is formed partially drained,

(ii)

a spray binder application post, impregnation (device "cascade" or "coating machine in curtain ") or go through a bath with an aqueous composition based on urea-formol resin plasticized with acetate and Acrylic resin, which deposits a quantity of binder of 19%, by weight of dry matter with respect to the weight of the veil,

(iii)

a drying and crosslinking stove with several temperature zones from 135 to 215ºC, in which the veil circulates with an average residence time of the order of 30 seconds, and preferably, slightly less than 30 seconds.

The veil poses no manufacturing problem and is obtained with a weight of 50 g / m2, a thickness of 0.3 mm and a porosity of 1,580 L / m2.

This veil undergoes resistance tests mechanical at room temperature and at high temperature, whose Results are listed in Table 1 below.

Tensile strength

From the veil sample, 10 are cut specimens in the longitudinal direction and 10 specimens in the direction transverse, with 250 mm length and 50 mm width. The test tube between the jaws of a traction machine and is operated the dragging system of the movable jaw until the breakage of the test tube; the breakage force values are then recorded (in Newton) and elongation at break (as a percentage of nominal length).

The resistance measurement is also performed at traction at 250 ° C under a fixed load equal to 10% of the value of break measured previously and the time needed to measure reach the test piece breakage.

Tear resistance

From the sample of the veil, 10 are cut specimens in the longitudinal direction and 10 specimens in the direction transverse, 100 mm long and 50 mm wide. In each test piece, from the edge of a small side, a cut is made  clean parallel to the large sides, halfway from the sides large and with a length of 50 mm. In a traction machine, it regulates the distance between the jaws so that it is equal to 50 mm, the specimens are placed in the jaws and the dynamometer regulating the separation speed to 100 mm / min. Be take note of the maximum load (in N) when the specimen is completely dissociated into two parts. The tear resistance is Express with the average of ten measures.

The veil of Example 1 has characteristics mechanical and dimensional stability very satisfactory. It has been used in a continuous membrane manufacturing line bituminous by impregnation with hot bitumen at approximately 200ºC, presenting a good aptitude for impregnation, and even giving the membrane a satisfactory static appearance.

Comparative example one

A veil is manufactured exclusively based on thread of glass, in the manner indicated in example 1. The veil has a weight of 50 g / m2, a binder rate of 24%, by weight of dry matter with respect to the weight of the veil, a thickness of 0.3 mm and a porosity of 2,000 L / m2. You undergo the same tests mechanical than the veil of example 1.

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Comparative example 2

Example 1 is reproduced with an organic fiber which does not meet the criteria of the invention. It is fiber polyester available from TERGAL FIBRES with the reference "1.6 dtex T110 mi-mat coupé ", equally capable of being dispersed in water, characterized by a 1.6 dtex title, a 12 mm cutting length, and a shrinkage percentage at 130 ° C in a steam atmosphere of 7%.

A veil of 50 g / m2 is manufactured, with a rate of binder of 24% by weight, a thickness of 0.3 to 0.4 mm and a porosity of 1,700 L / m2.

Manufacturing poses problems at the end of the line, since the formation of folds is observed at the exit of the stove, which can be attributed to a phenomenon of thermal contraction of organic fiber.

As the mechanical tests show, the veil It has a weak mechanical resistance, deteriorated with respect to classic glass veil. In particular, it is found that the Veil anisotropy has increased sharply. Besides, the Mechanical resistance at 250 ° C is non-existent.

This veil is not suitable for the realization of bituminous membranes

TABLE 1

Ahem. one Ahem. Comp. one jem. Comp. 2 Resistance to traction  Longitudinal (N / 5) cm) 214 165 150  \ hskip0.5cm Transversal (N / 5 cm) 133 93 70  \ hskip0.5cm Anisotropy 1.6 1.7 2.1  \ hskip0.5cm Elongation (%) 1.9 1.1 1.2 Tear resistance  Longitudinal \ hskip0.5cm (N) 3.0 1.5 3.2  \ hskip0.5cm Transversal (N) 3.5 1.7 3 250 ° C resistance > 4 min > 4 min 0 Folds over the line Do not Do not Yes

The invention has just been described in detail in the case of manufacturing a particular weight veil by way wet, for the application to the realization of membranes bituminous, but it is understood that the invention is not limited to this mode of implementation and encompasses, in particular, other techniques of manufacture of veil (dry track), other qualities of veils, eventually reinforced with continuous glass wires, as well as other products usable in covers and / or tightness.

Claims (9)

1. Veil based on usable fibers for the constitution of bituminous membranes, comprising glass fibers, organic fibers and a binder, obtained from an aqueous suspension of cut glass and organic fibers, characterized in that the organic fibers have a rate shrinkage, at a temperature of 130 ° C produced in a humid or steam atmosphere for 30 minutes, less than or equal to 5%. 2. Veil according to claim 1, characterized in that the organic fibers have a contraction at 130 ° C less than or equal to 3%. 3. Veil according to claim 1 or 2, characterized in that the organic fibers are based on a semi-crystalline polymer. 4. Veil according to any one of the preceding claims, characterized in that the organic fibers are polyester fibers, and especially poly (ethylene terephthalate). 5. Veil according to any one of the preceding claims, characterized in that the organic fibers have a size that allows the dispersion in water of the individual filaments. 6. Veil according to any one of the preceding claims, characterized in that the proportion of organic fibers is of the order of 5 to 30%, by weight with respect to the totoral weight of fibers. 7. Veil according to any one of the preceding claims, characterized in that the binder content is of the order of 15 to 30%, by weight with respect to the total weight of the veil. 8. Veil according to any one of the preceding claims, characterized by a weight of 30 to 150 g / m2. 9. Bituminous membrane comprising a substrate smeared, coated or impregnated with a bituminous matrix, characterized in that the substrate is a veil according to any one of the preceding claims.