IE920999A1

IE920999A1 - Filament-reinforced polyester inlay

Info

Publication number: IE920999A1
Application number: IE099992A
Authority: IE
Inventors: Bertrand Claude Weiter; Michael Schops
Original assignee: Hoechst Ag
Priority date: 1991-03-28
Filing date: 1992-03-27
Publication date: 1992-10-07
Also published as: JPH0598551A; FI921325A; NO921203L; EP0506051A1; FI921325A0; NO921203D0

Abstract

A filament-reinforced nonwoven fabric web is described, which is reinforced by sets of parallel reinforcement threads, the nonwoven fabric of which is composed of polyester fibres and has a weight per unit area of 20-200 g/m<2> and the parallel reinforcement threads of which are composed of polyester and have a similar maximum extension under tensile load to the polyester fibres of the nonwoven fabric. The nonwoven fabric web contains 1 to 20 reinforcement threads per cm of width and the reinforcement threads preferably have a titre of 50 to 200 dtex, a maximum extension under tensile load of 20 to 60% and a fineness-related maximum tensile load of 20 to 40 cN/tex. A process is also described for the production of this filament-reinforced nonwoven fabric web and use thereof for the production of roofing felts and roof linings.

Description

HOECHST AKTIENGESELLSCHAFT, a Joint Stock Company organized and existing under the laws of the Federal Republic of Germany, of D-6230 Frankfurt am Main 80, Federal Republic of Germany. -1IE 920999 - laHOECHST AKTIENGESELLSCHAFT HOE 91/F 097 Dr.VA/ Filament-reinforced polyester inlay Description The present invention concerns a filament-reinforced 5 nonwoven strip material made of polyester that is suitable in particular for use as inlay for bitumen felts and roofing underlays.

A filament-reinforced nonwoven strip material comprises nonwoven strips in which linear fibrous structures, for example filament bundles, monofilaments, staple yarns or multifilament yarns, are embedded, or otherwise positively held therein, in an essentially parallel and straight-line arrangement.

Filament-reinforced nonwoven strips that are reinforced by parallel filaments in the manner of a warp yarn sheet are known from DE-A-22 38 394. This publication is concerned primarily with a carpet backing made of glass fibers reinforced with warp yarns, preferably made of nylon.

DE-A-36 05 830 describes a carrier strip made of a laminate composed of a polyester web and a mineral fiber web, the mineral fiber web being reinforced by longitudinal threads made of a mineral material, preferably glass .

Similar layered nonwovens with high modulus reinforcing fibers are described in DE-A-39 41 189. The materials known from these two publications contain reinforcing fibers whose stress-strain characteristics differ greatly from those of the filaments making up the nonwoven. This different is utilized there on purpose in order to achieve a very high initial modulus for the laminate. In the case of the nonwoven described in DE-A-39 41 189, the reinforcing yarn applied to the web is also used as binding fiber. - 2 The materials described in these publications tend to delaminate under high thermal and mechanical stresses and therefore are not very suitable for manufacturing bituminized felts.

It is an object of the present invention to provide a nonwoven which combines a low basis weight with high mechanical stability and has very good processing properties not only in bituminization but also in the course of the further processing of the bituminized strip.

This object is achieved according to the present invention by a binder-consolidated polyester nonwoven strip material reinforced by sheets of parallel reinforcing yarns, the nonwoven comprising polyester fibers and having a basis weight of 20-200 g/m2 and the parallel reinforcing yarns being made of polyester yarns and having a similar breaking extension as the polyester fibers of the nonwoven.

The nonwoven part of the filament-reinforced nonwoven strip material according to the present invention can be made of staple or continuous filament fibers. Preferably, however, it is made of continuous filament fibers, constituting in particular a spunbonded nonwoven.

The reinforcing yarns can in principle be staple fiber yarns or continuous filament yarns, provided they exhibit the desired combination of breaking strength and breaking extension.

Because of their advantageous mechanical properties, continuous filament yarns are preferred.

Particularly suitable reinforcing yarns are fully orien30 ted yarns (FOYs) of polyester as described in Chemiefasern/Textilindustrie 37/89, 1987, pp. 794.

The filaments of the reinforcing yarns may also have nonround cross-sections, for example multilobal, dumbbellshaped or ribbon-shaped cross-sections. - 3 The reinforcing yarns of the nonwoven strip material according to the present invention preferably have a breaking extension of 20-60%. The tenacity is 20-40 cN/tex, preferably 30 to 35 cN/tex.

It is of particular importance that the filaments of the nonwoven and the reinforcing yarns should have a similar breaking extension. Similar for the purposes of the present invention means that the breaking extensions of nonwoven and reinforcing yarn should not differ by more than about 20%age points, preferably by not more than 10%age points, in particular by not more than 5%age points. In general, the breaking extension of the nonwoven filaments is chosen to be less than that of the reinforcing yarns. Nonwovens according to the present invention where a very high use loading is likely, however, can advantageously be reinforced with a yarn whose breaking extension is below that of the nonwoven filaments.

The linear density of the reinforcing yarn is advantage20 ously from 50 to 200 dtex. In special cases, where a lower or a particularly high mechanical strength are desired, a lower or higher linear density for the reinforcing yarn may of course also be indicated.

The boiling water shrinkage of the reinforcing yarn is preferably from 5 to 10%. The hot air shrinkage at 200eC is preferably from 8 to 10%.

The reported values for the boiling water shrinkage and the hot air shrinkage at 200 °C were determined as laid down in German Standard Specification DIN 53 866.

The filament-reinforced nonwovens according to the present invention contain from 1 to 20, preferably from 2 to 13, reinforcing yarns per cm of web width.

The polyester material used can in principle be any kind suitable for fibermaking. Polyesters of this type consist - 4 predominantly of units derived from aromatic dicarboxylic acids and from aliphatic diols. Widely used aromatic dicarboxylic acid units are the divalent radicals of benzenedicarboxylic acids, in particular of terephthalic acid and of isophthalic acid; widely used diols have 2-4 carbon atoms, with ethylene glycol being particularly suitable. Of particular advantage are nonwoven strip materials according to the present invention which consist of a polyester material which is not less than 85 mol% polyethylene terephthalate. The remaining 15 mol% are then composed of dicarboxylic acid units and glycol units, which act as modifiers and which make it possible for the person skilled in the art to influence in a specific manner the physical and chemical properties of the filaments to be produced. Examples of such dicarboxylic acid units are radicals of isophthalic acid or of aliphatic dicarboxylic acid, for example glutaric acid, adipic acid or sebacic acid; examples of modifying diol radicals are those of long-chain diols, for example of propanediol or butanediol, of di- or triethylene glycol or, if present in a minor amount, of polyglycol having a molecular weight of about 500-2000.

Particular preference is given to polyesters which contain not less than 95 mol% of polyethylene tereph25 thalate, in particular those made of unmodified PET.

As binders the nonwovens according to the present invention may contain for example the customary polymers which are applied in the form of dispersions. However, particular preference is given to those nonwovens according to the present invention which have been consolidated by means of fusible binders or thermomechanically.

Particular preference is also given to those filamentreinforced nonwoven strips according to the present invention which constitute a combination of preferred features. - 5 The nonwovens according to the present invention are prepared by depositing the fiber material onto a moving surface. Depending on whether staple fibers or, as preferred, continuous filament fibers are to be deposi5 ted, known fiber-depositing elements are used. To deposit continuous filament fibers it is advantageous to use spinnerette manifolds from which a fiber curtain is spun into a spinning and drawing cell within which the fibers, through the action of a stream of fluid, are simultaneously cooled and accelerated and hence drawn.

The reinforcing yarns are advantageously introduced off a warp beam, unwinding from which the yarns pass in between two web layers being deposited by two successive (in the transport direction) rows of depositor elements on the same surface.

Apparatus suitable for this process has been described in DE-A-23 10 542 and DE-A-39 41 189.

The choice of reinforcing yarn for manufacturing the filament-reinforced nonwoven according to the present invention is made according to the criteria specified above for this yarn.

The nonwoven is consolidated in a conventional manner by application of, for example spraying with, binder solutions or dispersions or alternatively, and preferably, by the incorporation of fusible binders and a subsequent heat treatment at a temperature at which the fusible binder melts and binds the load-carrying filaments of the nonwoven together at their crossing points.

The fusible binder is particularly advantageously intro30 duced into the web in the form of binder filaments. They can take the form of separate filaments, being spun for example from separate holes in the spinnerette manifold and uniformly distributed in the descending fiber curtain, or they can be in the form of a sheath or side surface of all or some of the load-carrying filaments, provided appropriate holes for spinning core-sheath filaments or side-by-side bicomponent filaments are provided in the spinnerette manifold. - 6 A further preferred way of consolidating the nonwoven according to the present invention consists in thermomechanical consolidation, which is likewise known per se and customarily effected by calendering with a hot calender.

The nonwoven strips according to the present invention do not delaminate, not even under extreme thermal-mechanical conditions.

The strength of the strips in the longitudinal direction by far exceeds the customary values of nonwovens of a similar basis weight. Also up is the penetration resistance, as measured by the mandrel penetration test of DIN 54 307. This results in appreciably improved ease and efficiency of laying the bituminized roofing felts according to the present invention on the roof. These surprising advantages of the reinforcing strip according to the present invention are presumably due to the homogeneous stress-strain characteristics of nonwoven and reinforcing yarn.

The present invention further provides a bituminized roofing felt and a bituminized roofing underlay, which each contain a filament-reinforced nonwoven strip material according to the present invention as support. These bituminized roofing felts or underlays are manufac25 tured by impregnating and/or coating the reinforcing strips according to the present invention with molten bitumen in a conventional manner.

Claims

1. HOE 91/F 097

What is claimed is: 5 1. A filament-reinforced nonwoven strip material reinforced by sheets of parallel reinforcing yarns, wherein the nonwoven comprises polyester fibers and has a basis weight of 20-200 g/m 2 and the parallel reinforcing yarns are made of polyester and have a similar breaking extension as the polyester fibers of the nonwoven. 10 2. The nonwoven strip material of claim 1, wherein the nonwoven is a filament nonwoven comprising filaments of polyethylene terephthalate.

3. The nonwoven strip material of at least one of the above claims, wherein the reinforcing yarn has a breaking extension of from 20 to 60%. 15

4. The nonwoven strip material of at least one of the above claims, wherein the reinforcing yarn has a tenacity of from 20 to 40 cN/tex, preferably from 30 to 35 cN/tex. 20

5. The nonwoven strip material of at least one of the above claims, containing from 1 to 20, preferably from 2 to 13, reinforcing yarns per cm of width.

6. The nonwoven strip material of at least one of the above claims, wherein the reinforcing yarn linear density is from 50 to 200 dtex. 25

7. The nonwoven strip material of at least one of the above claims, wherein the boiling water shrinkage of the reinforcing yarns is from 5 to 10%. 30

8. The nonwoven strip material of at least one of the above claims, wherein the reinforcing yarns have a hot air shrinkage at 200°C of from 8 to 10%. HOE 91/F 097

9. The nonwoven strip material of at least one of the above claims, wherein the nonwoven has been consolidated by means of a binder or thermomechanically.

2. 5 10. A bituminized strip material for use as roofing felt or underlay, containing a filament-reinforced nonwoven strip material as claimed in claim 1 as support.

11. A process for manufacturing a filament-reinforced 3. 10 nonwoven by depositing staple or continuous filament fibers on a moving surface using known fiber-depositing elements and introducing the reinforcing yarns off a warp beam, unwinding from which the yarns pass in between the layers of deposited fiber masses 15 between two successive (in the transport direction) rows of depositor elements working to the same surface, and consolidating the nonwoven in a conventional manner by applying bonding agents, by incorporating fusible binders and subsequent heat treat20 ment at a temperature at which the fusible binder melts and binds the load-carrying filaments of the nonwoven together at their crossing points, or by thermomechanical consolidation, which comprises depositing the polyester fibers to a basis weight of 25 20-200 g/m z and feeding in between the depositor elements reinforcing yarns made of a polyester material which have a similar breaking extension as the polyester fibers of the nonwoven. 30

12. The process of claim 11, wherein from 1 to 20 reinforcing yarns are introduced per cm of web width. 4.

13. The process of claim 11, wherein the reinforcing yarns introduced have a breaking extension of from 35 20 to 60%. HOE 91/F 097 5. 14.

14. 6. 15. 5 7. 16.

15. 5

16. 18. 18. 19. 19. 20. 20. The process of claim 11, wherein the reinforcing yarns introduced have a tenacity of from 20 to 40 cN/tex. The use of a filament-reinforced nonwoven of claim 1 for manufacturing roofing felts and underlays. A filament-reinforced nonwoven strip material according to claim 1, substantially as hereinbefore described. A bituminized strip material according to claim 10, substantially as hereinbefore described. A process for manufacturing a filament-reinforced nonwoven strip material according to claim 1, substantially as hereinbefore described. A filament-reinforced nonwoven strip material according to claim 1, whenever manufactured by a process claimed in a preceding claim. Use according to claim 15, substantially as hereinbefore described.