SK287629B6 - Glass fibre mat and use thereof for built-up roofing - Google Patents

Abstract

A fibre mat useful for forming bituminous membranes, comprising glass fibres, organic fibres and a binder, characterised in that the organic fibres have a shrinking ratio at 130 DEG C not more than 5 %. The mat also concerns a bituminous membrane comprising a substrate coated, lined or impregnated with a bituminous matrix, wherein the substrate consists of said mat. The mat and the membrane are useful for roofing and/or waterproofing.

Description

The present invention relates to the field of materials in a fiber-based film. More particularly, it relates to a glass film useful as a substrate for the manufacture of products coated, impregnated or impregnated with bitumen, in particular for use in covering and / or sealing.

BACKGROUND OF THE INVENTION

It is known in the art of covering or sealing to use bituminous membranes by applying them to a surface to be covered or sealed. These membranes are generally formed by a substrate in a film, coated or impregnated with a bituminous matrix.

The materials in the film may be of various kinds and are usually obtained from organic or mineral fibers, preferably non-woven.

Glass films are particularly preferred among usable materials since they guarantee the dimensional stability of the bituminous membrane over time.

The glass films can be obtained by any known method, in particular the so-called glass foil. by the wet route, mainly described in "The Manufacturing Technology of Continuous Glass Fibers", K. L. Loewenstein, Ed. Elsevier, 2nd Ed., 1983, p. This method, which is related to papermaking technology, comprises preparing an aqueous slurry of cut glass fibers, depositing a slurry of the slurry on a filter lining that is suctioned to remove some of the water from the deposited layer, applying a binder mixture to the wet layer, drying the film and crosslinking the binder in the furnace, and then processing the film in the desired manner. The final product is in the form of a relatively thin film (thickness of the order of 0.2 to 0.8 mm), usually wrapped in rolls.

The binder is often an aqueous mixture based on urea-formaldehyde resin, which resin has sufficient temperature resistance for the temperatures used in subsequent bitumen impregnation.

However, glass foils have the disadvantage of a relatively low tear strength, which reduces the convenience of use and, in particular, forces the user to take precautions in this respect when handling the membrane to form or place it on the roof.

This disadvantage can be overcome by complex substrates which bond the organic fiber-based film having good tear strength and the glass grid giving the whole dimensional stability. However, these complexes, which combine two intermediate products, are labor intensive.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a glass-based material whose tear strength is improved without complicating the production of conventional film.

EP-A-0 763 505 discloses a glass fiber mat for the production of bituminous roofing, the strength of which is improved by a binder based on urea formaldehyde treated with a self-crosslinkable vinyl additive. In this mat, a smaller proportion of fibers need not be made of glass, being selected mainly from the group of organic fibers, such as e.g. Nylon®, polyester, polyethylene, or polypropylene. This document does not provide an accurate identification of these organic fibers, nor does it contain any specific example illustrating this possibility.

SUMMARY OF THE INVENTION

The present invention is based on the finding that many organic fibers are not suitable for the production of films and even have a very negative effect on the properties of the film when used for bituminous coverings, but a very precise selection of synthetic materials makes it possible to overcome this drawback.

Accordingly, it is an object of the present invention to provide a fiber-based film useful in the manufacture of bituminous membranes, including glass fibers and organic fibers, bonded by a binder, characterized in that the fibers have a shrinkage rate of 130 ° C less than or equal to 5%.

It should be noted that the term " glass sheet " or " glass mat " according to the invention includes materials well known to those skilled in the art of glass fiber products. They are thin film materials having a substantially isotropic structure, i.e. there is no predominant fiber orientation therein.

In practice, the film can be qualified by the "isotropic ratio" = tensile strength of the film in the machine direction of the tensile strength of the film in the transverse direction, which is generally of the order of 1, in particular of the order of 1 to 1.5. the random fiber orientation is generally obtained by using glass fibers in the form of cut strands, such as e.g. using said wet process.

The choice of organic fibers according to said criterion provides the film with good quality and in particular mechanical strength and temperature resistance, compatible with the later application of bitumen impregnation, while other fibers would provide the film with insufficient temperature resistance and / or mechanical strength.

In the first place, the organic fibers used to make the film have a high melting point, so as to prevent their degradation at all temperature stages of the film production, particularly during drying and crosslinking in the furnace, and when using the film, especially in contact with the bituminous binder. Generally, the organic synthetic material is selected to have a melting point greater than about 220 ° C.

According to the invention, the fibers are selected depending on their degree of thermal shrinkage. This quantity corresponds to the dimensional changes, in this case the shortening of the fiber after being exposed to a given temperature for a limited time. To determine this, the initial length L1 of the fiber before heating and then the final length Lf of the fiber are measured, with a shrinkage rate r equal to r = (Li-Lf) / Li (expressed as a percentage).

The indicative shrinkage rates of the invention are expressed for a temperature of 130 ° C maintained in a vapor environment for 30 minutes.

According to the invention, the shrinkage is chosen to be less than or equal to 5%, preferably 4%, in particular 3%, for example of the order of 2 to 3%.

Fibers of this quality can be obtained from semi-crystalline polymerization materials, especially those in which the spinning process allows the drawing to be carried out which increases their degree of crystallinity. Other production conditions, such as the presence of nucleating agents or a temperature factor, may also lead to the organization of the basic macromolecules, by which a polymer whose structure was initially amorphous, acquires a crystalline structure and becomes semi-crystalline.

The fibers corresponding to the claims of the invention can be found among polyester fibers, in particular between fibers of polyalkylene terephthalate and in particular of polyethylene terephthalate.

Preference is given to organic fibers adapted to the non-woven production processes by a wet route, which comprise a sizing enabling the individual fibers to be dispersed in the water.

The organic fibers may have different dimensions, the diameter of which may be on the order of 7 to 25 μπι in diameter, for a linear density of the order of 0.5 to 2 dtex. The fibers are preferably cut to a length of the order of one or several tens of millimeters, in particular 6 to 30 mm.

The effect of organic fibers is apparent from 5 wt. relative to the total weight of the fibers. The proportion of organic fibers is preferably on the order of 5 to 30%, in particular 20 to 30%, in particular about 25% by weight. relative to the total weight of the fibers.

As glass fibers according to the invention, conventional glass fibers are used for the production of foil, preferably in the form of fibers cut to a length of the order of about ten millimeters, in particular 6 to 30 mm, preferably approximately 10 to 20 mm, for example 12 to 18 mm. It is understood that a certain proportion of fibers (e.g. 5 to 10%) can be cut to a length of up to 100 mm. Finally, a continuous filament, in particular glass fiber, can be inserted into the film for consolidation in the longitudinal direction.

The binder used for the production of the film is preferably based on urea-formaldehyde resin, preferably treated with vinyl and / or acrylic additives in a manner known in particular from US-4,681,802, EP-A-0 763 505. The amount of binder generally corresponds to 15 to 30 % wt. solids relative to the film.

The foil is made with a weight usually used for glass foils of the order of 30 to 150 g / m ² , in particular 50 to 120 g / m ² .

Due to the difference in density between glass and organic fibers, at a given weight, the amount of mass in the film according to the invention is slightly greater than the amount of mass contained in the glass film, resulting in a relatively greater thickness and / or less porosity. For example, the porosity is of the order of 1500 to 1900 l / m ² for a 50 g / m ² film.

Since the film according to the invention is particularly suitable for use in sealing and / or covering, the invention also relates to a bituminous membrane comprising a substrate coated, coated or impregnated with a bituminous matrix, characterized in that the substrate is a film as described.

The bituminous matrix may be selected from those known: natural, modified or untreated bitumen or a synthetic binder, such as a "light binder", which in particular allows the membrane to acquire a decorative color.

DETAILED DESCRIPTION OF THE INVENTION

The following non-limiting examples illustrate the invention in more detail.

Example 1

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

- 75 wt. chopped glass fiber E having a fiber diameter of 10 gm and a linear density of 360 tex, cut to a length of 12 mm,

- 25 wt. cut polyester yarn, manufactured by KURARAY under the designation EP 133, adapted for paper dispersible paper processes. This yarn has a fiber diameter of 12 μηι and a linear density of 1.4 dtex and is cut to a length of 15 mm. It is a polyethylene terephthalate yarn, pulled to increase its crystallinity, having a shrinkage rate of the order of 2% at 130 ° C in a humid environment for 30 minutes and a shrinkage rate of 3% at 170 ° C in a dry environment for 15 minutes.

The fiber suspension, also containing other conventional additives, namely defoaming agents, dispersing agents, viscosity modifiers, etc., is processed under standard conditions on a film making plant, comprising (i) a hydroformate on which a partially dewatered wet film is formed, (ii) ) the application site of the binder by spraying, brushing (curtain coating or curtain coater) or passing through an aqueous mixture based on urea-formaldehyde resin softened with acetate and acrylic resin, where a quantity of binder corresponding to 19% by weight is applied to the film . (iii) a drying and crosslinking oven with several temperature ranges from 135 to 215 ° C, through which the film passes with an average residence time of the order of 30 seconds, preferably slightly below 30 seconds.

There are no problems with the production of the film and the film obtained has a grammage of 50 g / m ² , a thickness of 0.3 mm and a porosity of 1580 l / m ² s.

Tensile strength and temperature tests were performed on this film, the results of which are shown in Table 1.

Tensile strength

From the film sample, 10 test pieces in the longitudinal direction and 10 test pieces in the transverse direction, which are 50 mm wide and 250 mm long, are cut. The test specimen is mounted between the jaws of the tensile testing machine and the movable clamp drive device is lowered until the specimen breaks: then the tear strength (in Newtons) and the elongation at break (percentages in nominal length) are recorded.

A tensile strength measurement at 250 ° C at a constant load equal to 10% of the first measured value of the strength shall also be measured, taking into account the time taken to tear the sample.

Tear strength

From the film sample, 10 test specimens in the longitudinal direction and 10 test specimens in the transverse direction, 50 mm wide and 100 mm long, are cut. A 50 mm clean cut shall be made on each test piece, starting at the edge of the shorter side at half the distance between the longer sides and parallel to the longer sides. On the tensile testing machine, set the distance between the jaws to be equal to 50 mm, attach a test sample between the jaws and lower the dynamometer, setting the rate of climb to 100 mm / min. The maximum load (in N) shall be recorded when the test piece is completely torn into two parts. Tear strength shall be expressed as the average of ten measurements.

The dimensional stability and mechanical properties of the film of Example 1 are very satisfactory. The film was processed on a continuous production line to a bituminous membrane by impregnating it with hot bitumen at a temperature of about 200 ° C, having good impregnation capability and even giving the membrane a very strong appearance. Comparative Example 1

The method described in Example 1 produces a film, but exclusively based on glass fibers. The film has a grammage of 50 g / m ² , a binder content corresponding to 24% by weight. dry matter with respect to foil weight, 0.3 mm thickness and porosity 2000 l / m ² s. This film is subjected to the same mechanical tests as the film of Example 1. Comparative Example 2

Example 1 is repeated, but using organic fibers that do not meet the criteria of the invention. These are polyester fibers sold by TERGAL FIBERS under the designation "1.6 dtex TI 10 mi-mat coupé" (1.6 dtex TI 10 semi-cut), which are equally dispersible in water, characterized by a linear density of 1.6 dtex, cut to 12 mm long and having a shrinkage rate of 130 ° C in a steam environment of 7%.

A foil having a grammage of 50 g / m ² , a binder content of 2% by weight, a thickness of 0.3 to 0.4 mm and a porosity of 1700 l / m ² s is produced.

Manufacturing creates problems at the end of the line, since at the outlet of the furnace, formation of creases can be observed which can be attributed to the thermal shrinkage of the organic fiber.

As can be seen from the results of mechanical tests, the film has a low mechanical strength, deteriorated compared to conventional glass film. In particular, the film has a very increased anisotropy. Furthermore, the film has no mechanical strength at 250 ° C.

This film is therefore not suitable for the production of bituminous membranes.

Table 1

Pr. 1 Por. pr. 1 Por. pr. 2 TENSILE STRENGTH Longitudinal direction (N / 5 cm) 214 165 150 Transverse direction (N / 5 cm) 133 93 70 anisotropism 1.6 1.7 2.1 Extension (%) 1.9 1.1 1.2 Tear strength Longitudinal direction (N) 3.0 1.5 3.2 Transverse direction (N) 3.5 1.7 3.0 STRENGTH AT 250 ° C > 4 min. > 4 min. 0 CREATE CREATION ON THE LINE not not Yes

The invention has been described in detail by way of example by making a film with a particular wet weight for use in the manufacture of bituminous membranes. However, it is understood that the invention is not limited to this embodiment and includes in particular other methods of making the film (dry road), other classes of films, optionally reinforced with continuous glass fibers, as well as other products useful for covering and / or sealing.

PATENT CLAIMS

Claims (9)

A fiber-based film usable for the production 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 temperature of 130 ° C formed in a vapor environment or in a humid environment for 30 minutes a shrinkage rate of less than or equal to 5%. Film according to claim 1, characterized in that the organic fibers have a shrinkage rate at 130 ° C of less than or equal to 3%. The film according to claim 1 or 2, characterized in that the organic fibers are based on a semi-crystalline polymer. Film according to any one of the preceding claims, characterized in that the organic fibers are polyester fibers, in particular of polyethylene terephthalate. A film according to any one of the preceding claims, characterized in that the organic fibers comprise a size enabling the individual fibers to be dispersed in the water. Film 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. relative to the total weight of the fibers. Film 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 film. Film according to any one of the preceding claims, characterized in that it has a grammage of 30 to 150 g / m ² . A bituminous membrane comprising a substrate coated, coated or impregnated with a bituminous matrix, characterized in that the substrate is a film according to any one of the preceding claims. End of document