US3259535A

US3259535A - Method and apparatus for treating mats of a loose fibrous or filamentary structure

Info

Publication number: US3259535A
Application number: US181251A
Authority: US
Inventors: Roderich Wilhelm Graeff
Original assignee: Detag
Current assignee: Flachglas Wernberg GmbH
Priority date: 1961-03-24
Filing date: 1962-03-21
Publication date: 1966-07-05
Anticipated expiration: 1983-07-05
Also published as: NL276105A; CH393729A; DE1181900B; LU41357A1; BE615328A; GB948040A; DK104077C

Description

m VL /vm/e A T TOR/V5 YS R. W. GRAFF METHOD AND APPARATUS FOR TREATING MATS OF A LOOSE July 5, 1966 FIBROUS OR FILAMENTARY STRUCTURE Filed March 21, 1962 PRIOR ART Rooemcu Wnu-usm GRRFF United States Patent 3,259,535 METHOD AND APPARATUS FOR TREATING MATS OF A LOOSE FIBROUS 0R FILAMEN- 'TARY STRUCTURE Roderich Wilhelm Graft, Burgberg, Villingen, Black Forest, Germany, assignor to Deutsche Tafelglas Aktiengesellschaft Detag, Furth, Bavaria, Germany Filed Mar. 21, 1962, Ser. No. 181,251 Claims priority, application Germany, Mar. 24, 1961, D 35,735 6 Claims. (Cl. 156-324) The present invention relates to a method and an apparatus for treating mats of materials of a loose fibrous or filamentary structure in a rolling process and for protecting such mats during this process from the danger of being damaged by the traction which is exerted thereon by the rollers and which may be of such a strength as to endanger the cohesion of the fibers or threads of the mat.

Although the present invention is applicable to the manufacture and treatment of various kinds of materials, it will hereafter be described with reference to the manufacture of mats of a reinforcing material which is impregnated with a synthetic resin and upon which cover sheets are applied. This reinforcing material may consist, for example, of glass fiber mats, that is, of a product with a fibrous structure. When the glass fibers are impregnated with a liquid resin, for example, a polyester resin, it is very important that any air or gases which are occluded in the mat be expelled therefrom. This is generally attained by passing the impregnated met through at least one pair of rollers which exert a pressure upon the mat to mold the same to a suitable shape and consistency in accordance with the particular purpose of the desired product. By this rolling operation, the .air and gases which are occluded in the mat are driven out and any excess of impregnating material is also expelled from the mat. In order to maintain the fibrous mat free of any air or gases after it has been impregnated, it is conventional to cover both sides of the mat with a sheet material.

Inasmuch as such a fibrous mat possess-es only a very low solidity until the impregnating material has set, it is easily affected even by minor irregularities during the rolling process with the result that under the pressure of the rollers and the tension exerted upon the material, the mat may yield and be unevenly extended and may even tear.

Although various efforts have in the past been made to overcome these disadvantages, these efforts have only been partly successful and usually they also increased the cost of the product or resulted in a product of a poor appearance.

'It is an object of the present invention to provide a method and an apparatus for manufacturing and treating mats of a fibrous or filamentary structure and for attaining a product of a superior quality.

This and other objects of the invention as Well'as the various features and advantages thereof will become more clearly apparent from the following detailed description which is to be read with reference to the accompanying diagrammatic drawings, in which:

FIGURE 1 illustrates the conventional method and apparatus for producing a resin-impregnated mat;

FIGURE 2 illustrates the method according to the invention and shows a side view of the new apparatus; while FIGURE 3 shows a plan view of the apparatus according to FIGURE 2.

According to the conventional method, :as illustrated in FIGURE 1, the reinforcing material, for example, a glass fiber mat 1, is Wound from a supply roll 2 and fed to 3,259,535 Patented July 5,1966

an impregnating table 3 .and upon a lower cover sheet 4 which is supplied from a pair of rolls 5. After being impregnated on table 3 by suitable means, as indicated diagrammatically at 6, mat 1 passes with the lower cove-r sheet 4 to a pair of

rollers

7 and 7", while at the same time an upper cover sheet 8 is supplied from a supply roll 7 to the upper roll 7' and then to mat 1 which is thus impregnated as well as covered on both sides. Roller 7' has not only the purpose to apply the upper-cover sheet 8 upon mat 1 but also at the same time to exert together with the lower roller 7 a pressure upon the mat in order to expell any occluded air or gases as well as any excessive impregnating material. In this operationthe particular difiiculties occur which are overcome by the present invention. Since the fibrous mat has a'rather low solidity, much lower than that of a web of fabric, it will, when subjected to an uneven pressure or tension, also yield to a greater extent at those points where a greater force is applied. Such irregularities cann'ot be entirely avoided in the rolling operation. They may be due to various factors, for example, to an uneven distribution of the impregnating material. The danger then occurs that the mat will not only be extended unevenly but may even tear. Even the distribution of the impregnating material in the mat may then become uneven. These difiiculties increase with the increase in the viscosity of the resins applied in the impregnation of such mats. In other words, since high-quality products usually require highly viscous resins, the manufacture of such products also becomes exceedingly difiicult and thus very expensive, also because of'the great amount of rejects caused by these difiiculties.

In order to avoid such occurrences which greatly impair the quality of the finished products, threads 9, for example, of nylon, have previously been fed between the mat and the upper cover sheet 8, as indicated in FIG- UR-E 1. Although this method improved the strength of the material and its resistance to the mentioned irregularities, it increased the cost of the material considerably and also had the disadvantage that the threads remained in the product and were visible on or through the cover sheet.

The present invention retains the concept of employing threads for reinforcing the impregnated mat during the rolling operation; however, instead of embedding such threads in the mat so as to remain therein, the invention employs such threads in a substantially stationary position relative to the moving mat, as illustrated in FIG- URES 2 and 3. Any suitable number of such threads 11 extending substantially parallel to each other and to the mat 1 are then inserted between the moving mat and cover sheet 8 so that'after the molding or rolling operation by the rollers 7' and 7", the impregnated mat is withdrawn from the threads and thus moved away without them.

The apparatus according'to the invention as shown in FIGURES 2 and 3 operates in the same manner as the conventional apparatus according to FIGURE 1,'-that is, the apparatus from which the threads 9 are omitted, except that it is additionally provided with a crossbar 10 on which a row of threads 11 are secured which extend from a point in front of the rollers 7' and 7" loosely to a point for a certain distance behind these rollers, as indicated in FIGURE 3.

The threads 11 should consist of a material which remains unaffected by the impregnating material, for example, of steel, glass, nylon, polyester, or the like, and they should be spaced from each other at a distance which depends upon the type of material to be impregnated and the viscosity of the impregnating material. The most suitable distance usually amounts to about 5 to 30 mm.

The new method and the new apparatus in which the threads are held in a stationary position relative to the moving mat may also be applied to other kinds of fibrous mats than those previously described, in which there is a danger that, due to an unequal distribution of forces, the structure of the mat might be destroyed during the molding or rolling operation.

Although in the drawings it is only indicated that the threads 11 are applied upon the upper side of the mat, they may additionally also be applied upon the lower side. This is of particular advantage if the mat is not fed to the squeezing rollers in the horizontal direction but at an oblique or vertical direction.

The new method and new apparatus not only save the cost of the embedded threads, which previously remained in the products but the products which are now attained are also of a superior quality since they no longer contain the threads. Furthermore, it is now possible to Vary the ratio between the reinforcing material and the impregnating material as much as desired and there is no longer any danger that the use of a very viscous impregnating material might cause an uneven extension or even a tearing of the mat.

Although my invention has been illustrated and described with reference to the preferred embodiment thereof, I wish to have it understood that it is in no way limited to the details of such embodiment but is capable of numerous modifications within the scope of the appended claims.

Having thus fully disclosed my invention, what I claim is:

1. A method of treating mats of loose fibrous materials using means for feeding the mat, means for guiding at least one cover sheet into association with a side of the mat, means for applying a fluid hardenable resin to at least one side of the mat on the same side as the cover sheet and before the cover sheet is applied to the respective side, smooth cooperating pressing rollers for pressing the cover sheet and the mat after the plastic material is applied, and a stationary member having a plurality of fixed length long and flexible substantially parallel threads extending along the path of feed of the mat, comprising feeding the mat along a feed path, applying the plastic material to at least one side of the mat as the mat is fed, permitting the threads of the stationary member to fall onto the plastic material applied to the mat and to extend therealong as the mat is fed, applying the cover sheet over the threads, pressing the mat with the cover sheet thereon and the threads therebeneath, and then withdrawing the mat with the ,cover sheet away from the threads so that the threads are withdrawn from under the cover sheet.

2. A method according to claim 1, wherein said mat is continuously fed and continuously pressed as it is fed at a location where the threads of the stationary member are present below the cover sheet.

3. A device for treating mats of loose fibrous material, comprising means for feeding the mat along a feed path, means for applying a fluid, hardenable resin to at least one side of the mat as it is being fed, a stationary member having a plurality of fixed length long and flexible laterally spaced substantially parallel threads disposed along the feed path of said mat with the threads thereof falling onto the plastic material which has been applied to said mat, means for applying a cover sheet over the mat on the side with the plastic material and the threads, smooth surface means for continuously pressing the mat as it is being fed at a location overlying the cover sheet and the threads, said feeding means being effective to withdraw the mat with the plastic material and the cover sheet away from the threads after pressing whereby the threads are removed from the cover sheet after the mat with the cover sheet and plastic material has been pressed.

4. An apparatus for preparing composite sheet material using a mat of loose fibrous material, comprising a support, means for moving a carrier sheet along said support, means for directing a mat onto the moving carrier sheet, means for impregnating the mat with a fluid hardenable synthetic resin, stationary holding means having a plurality of flexible substantially parallel laterally spaced threads of limited length attached thereto and loosely extending longitudinally along said support in the direction of feed of said carrier sheet, means for applying a top sheet over the threads and the resin applied to said mat as said carrier sheet with the mat is being advanced, smooth surface means for pressing the moving resin impregnated mat at a location to overlie said cover sheet and said threads, said threads projecting beyond said pressing means a short distance, said means for moving a carrier sheet being effective to withdraw the pressed mat away from said pressing means and the stationary threads to drag the threads over the surface of the mat below the covering sheet as the composite sheet material is being drawn away.

5. Apparatus for preparing composite sheet material comprising a support, means for moving a carrier sheet along said support, means supplying a mat of material of loose structure onto the moving carrier sheet, means for impregnating the mat with a fluid synthetic resin, stationary holding means, a plurality of flexible substantially parallel threads of limited length attached at their rear ends to the said holding means and loosely extending longitudinally along the support, smooth surfaces means for squeezing the moving impregnated fibrous layer forwardly of the said thread holding means, the said threads projecting a short distance beyond said squeezing means, and means for withdrawing the squeezed fibrous layer from said squeezing means permitting with the stationary threads to drag over the surface of the fibrous layer as the layer is moved away therefrom.

6. Apparatus according to claim 5, including means for applying a cover sheet over said mat and saidthreads and wherein said squeezing means comprises opposed rotating rollers through which said carrier sheet, impregnated mat with threads thereon, and cover sheet are moved.

References Cited by the Examiner UNITED STATES PATENTS 2,260,081 10/1941 Lefebure et al. 15639 2,370,393 1/1945 Brubacher l61l39 X 2,782,458 2/ 1957- Emmert et al. 2,931,421 1/ 1961 Schuller. 2,969,301 1/1961 Finger. 3,158,181 11/1964 Gore 156-292 X EARL M. BERGERT, Primary Examiner. C. B. COSBY, R. J. CARLSON, Assistant Examiners.

Claims

1. A METHOD OF TREATING MATS OF LOOSE FIBROUS MATERIALS USING MEANS FOR FEEDING THE MATS, MEANS FOR GUIDING AT LEAST ONE COVER SHEET INTO ASSOCIATION WITH A SIDE OF THE MATS, MEANS FOR APPLYING A FLUID HARDENABLE RESIN TO AT LEAST ONE SIDE OF THE MAT ON THE SAME SIDE AS THE COVER SHEET AND BEFORE THE COVER SHEET IS PPLIED TO THE RESPECTIVE SIDE, SMOOTH COOPERATING PRESSING ROLLERS FOR PRESSING THE COVER SHEET AND THE MAT AFTER THE PLASTIC MATERIAL IS APPLIED, AND A STATIONARY MEMBER HAVING A PLURALITY OF FIXED LENGTH LONG AND FLEXIBLE SUBSTANTIALLY PARALLEL THREADS EXTENDING ALONG THE PATH OF FEED OF THE MAT, COMPRISING FEEDING THE MAT ALONG PATH APPLYING THE PLASRIC MATERIAL TO AT LEAST ONE SIDE OF THE MAT AS THE MAT IS FED, PERMITTING THE THREADS OF THE STATIONARY MEMBER TO FALL ONTO THE PLASTIC MATERIAL APPLIED TO THE MAT AND TO EXTEND THEREALONG AS THE MAT IS FED, APPLYING THE COVER SHEET OVER THE THREADS, PRESSING THE MAT WITH THE COVER SHEET THEREON AND THE THREADS THEREBENEATH, AND WITHDRAWING THE MAT WITH THE COVER SHEET AWAY FROM THE THREADS SO THAT THE THREADS ARE WITHDRAW FROM UNDER THE COVER SHEET.