DE1269990B - Process for the production of binder-strengthened fibrous webs - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY GERMAN Wfl? TW> PATENT OFFICE

EDITORIAL

Int. Cl .:

Number:
File number:
Registration date:
Display day:

D 04h

German class: 8 h-7

P 12 69 990.0-26
March 28, 1964
June 12, 1968

The invention relates to a method for producing binder-reinforced fibrous webs with at least increased fiber density on a surface compared to the nonwoven core.

For the production of such fiber webs, a method is already known in which one fresh produced, uncured fiber fleece on one or more surfaces with a relatively dense, hardened Fiber fleece covered and the layering obtained subsequently to form a uniform fiber fleece hardens with layers of different densities. Continuous or discontinuous processes of this type are described in U.S. Patent Application 750,654 and U.S. Patent 2,868,684, respectively.

However, these known methods require several separate work stages or use several different starting materials. There is therefore a strong need for a simple one and inexpensive method, after which one from a uniform fiber material in one Continuous operation with binder-reinforced fibrous webs with one or more surface areas can produce increased fiber density.

To eliminate these disadvantages of the known method and to achieve a simple and economical discontinuous or preferably continuous production of binder-solidified Fibrous webs of the type indicated above, the invention was based on the technical problem placed, a starting material that is homogeneous in terms of fiber material and binding agent is gradually converted into to transfer the solidified state by differentiating the fiber density.

This problem is solved by starting from a starting material which is of a uniform nature with regard to the fibers and the binder content and in which the binder can be hardened by heat. According to the invention, the initial fleece is first supplied with a sufficient amount of heat for the binding agent hardening in the heat supply area by conduction and the application of pressure, then the material to be treated is relieved of pressure and then the pressure-relieved material to be treated is completely cured by further supply of heat. This measure enables the initial nonwoven cured in the surface area to retain its fiber density unchanged after the pressure has been relieved, while the fibers in the not yet hardened nonwoven core area expand due to their inherent elasticity and are arranged in a lower fiber density. Through the subsequent printing process for the production of
bonded fiber nonwovens

Applicant:

Gustin-Bacon Manufacturing Company,

Kansas City, Mo. (V. St. A.)

Representative:

Dr.-Ing. K. Boehmert

and Dipl.-Ing. A. Boehmert, patent attorneys,

2800 Bremen, Feldstr. 24

Named as inventor:

Eugene Francis Wenzl, Kansas City, Mo .;

Sidney Lawrence Williams,

Park Ridge, JIl. (V. St. A.)

Claimed priority:

V. St. v. America April 1, 1963 (269 640) - -

loose heat treatment, the fleece core with its lower fiber density is also cured and form stabilized.

To carry out the method according to the invention, the uncured fiber fleece with a or both surfaces with one or more heated cylinder bodies with smooth or patterned Surface are brought into contact. When using rollers with a profile-bearing surface Accordingly, fibrous webs with a corresponding surface pattern are obtained. The heated, Continuous rolls of the uncured fiber fleece can also be fed to cylindrical elements will. Depending on the desired end product, the surface areas to be produced can be increased Fiber density by adding binder before contact with the heated cylinder bodies be modified.

The heated cylinder bodies passed through first do not yet cause the Fiber fleece, since its thickness and the temperatures and pressures used are chosen so that only the near-surface areas of the fiber fleece are hardened. The fiber fleece hardened on the surface is then carried out through hardening ovens of the usual type for continuous hardening. Through appropriate

809 559/312

3 4

Choice of the process step that extends during the passage of the uncured leaving the roller 14 Nonwoven fabric exerted by the heated rollers in this or other conventional manner, for example pressure The surfaces heated in the process are designed according to the patent areas mentioned above densified according to the methods described for surface steps cured with a correspondingly higher density. 5 den. The length and mean diameter of the The inner areas of the fiber fleece are then under glass fibers, the type and amount of binding material, a lower pressure producing a corresponding ratio to the amount of fiber as well as the type and Hardened speaking lower density. The amount of other additives obtained can vary depending on the Hardened fiber fleece therefore consists of a uniformly desired properties of the fiber fleece borrowed fiber material, which can be varied in one or both io according to the purpose. The fiberglass Surface areas on a compared to can by conventional devices, for example fleece core higher fiber density is compressed. In the way by means of a centrifugal device or after In contrast to those produced by the previous process a continuous process, etc. by hardening together a stratification of several.

Ren cured fiber webs of different density 15 The loosely compacted fiber mass 16 is after

The products produced have the invention leaving the conveyor belt by one in one

produced nonwovens due to their single-layer, frame 17 arranged roller device with min-

only differently compacted structure at least two rollers 18 and 19 out, which on

significantly improved properties, in particular rotatable shafts 20 and 21 or rotatable as such

no tendency to split. 20 are stored in the frame 17. At least one of the

The unhardened rollers 18 and 19 used according to the invention have internal heating devices

Starting nonwovens can be made by conventional methods, lines of conventional type, for example gas burners

for example, in accordance with the USA. patents or other burners, which on the possibly

3 025 197, 2 946 371, 2 825 389, 2 778 759 and hollow shafts 20 and 21 may be arranged.

2 619151. With such confusion there are already numerous types of internal heating

F aservliesen also causes the rollers according to the invention, for example road rollers, are known,

necessary heating of the fleece by conduction requires the formation of the conventional heating

an extensive smoothing of the surface fibers. Tongue devices not further explained here

Such a, smoother, less frayed upper become.

surface also has the advantage of a paint 30 at least one of the rollers 18 and 19 is to absorb less paint, so that even with a frame 17 vertically adjustable, so that a smaller amount of paint a certain light reflection of the roller spacing is achieved in each case in comparison . In this way, the impairments occurring with the desired final thickness of the fiber fleece can be adjusted to a lower value. For the acoustic properties and the cost of performing the method of the invention, paint is reduced. When comparing it is essential that this roller spacing is smaller, manufactured according to the invention and without heat than the final thickness. For example, conventional fibrous panels produced for generating production use a fibrous nonwoven with a final thickness of 19 mm with sprayed-on topcoat layers in each case the same as the thickness and density of the conveyor belt with a layer thickness of about 250 mm the same as the rollers 18 and 19 with a roller spacing of color weight resulted in a considerably higher reflection. about 6.3 mm passed through. In Fig. 1 the In the following an arrangement suitable for the implementation of the roller spacing and the thickness of the fiber web for the invention is shown exaggeratedly large with reference to the drawing clarification, explanations. It shows 45. After passing through the rollers 18 and 19, F i g has. 1 is a schematic side view of a frontal fiber web that is shown in FIG. Appearance shown in FIG. 4, direction for carrying out the process according to the invention, with the surface areas passing a heated roller up to one of the areas shown in FIG. 2 is a schematic side view of a compression and curing time as well as the pressure and the changed device for carrying out the method according to the invention, which depends on the amount of heat supplied, the remaining core of FIG. 3 shows a schematic side view of a white fibrous nonwoven more or less completely lower device for carrying out the device which remains cured according to the invention. Since an elastic, uncured method and core area are to remain, the roller pressure in FIG. 4, a schematic longitudinal section through 55, must not be selected so high that the nonwoven fiber material no longer springs back along the line 4-4 in FIG. The amount of heat supplied must be sufficient in the area to be generated in the surface direction to be generated from a higher density area (not shown) that is supplied with a suitable heat-binding agent or resin for curing the direction Temperature to be hardened resin, for example a phenol mold-60 reach. In the illustration according to FIG. 4, aldehyde resin-sprayed glass fibers 11 with a central fiber fleece have an at least largely smaller diameter of, for example, 5 μ through a hardened core area 22 b and one or more feed channel 10 to an endless, perforated hardened surface area 22 α with a higher Dense conveyor belt applied, which runs on rollers 13 and on, in which the glass fibers largely smoothly in the. A useful 65 surface is anchored under the conveyor belt.

a vacuum chamber 15 is arranged so that the In one or more further frames 17

fibers sprayed with binding agent a loosely felted one, further rollers 18 and 19 can also be attached.

Form uncompacted mass 16. These up to the ordinance, for example only the upper or

5 6

only the lower or the upper and lower or the distance between the conveyor belts 51 and 52 corresponds

alternating upper and lower rollers to be heated to the desired thickness of the end product and should

can. Instead of the in FIG. 1 rolls shown to be as large as is necessary for a generation of the end

18 and 19 can also be used for product driven by rollers without an upstream pressure roller stage be provided, which would be required over a 5. The conveyor belts 51 and 52 are predetermined area continuously an equal-driven by rollers 53 and 54, which are in the frame generate moderate pressure. In this case too, 55 must be stored. After leaving the curing oven the fiber fleece first on a compared to 50, the hardened fiber fleece obtained in Thickness of the end product smaller thickness compacted a cutting device 56 with conventional cutting and the temperature as well as the pressure and heating rollers 57 and 58 are cut.

duration can be selected so that the desired over- In the in F i g. 3 shown, further Ausfühflächebereich down to the desired depth, but approximately form of a device for performing the not harden through to the core. The nonwoven fabric according to the invention, after the pressure has been released, must spring back at least to the number of fiber generation heads of the desired thickness of the end product at the center. After passing through the zone of high compression through the shaft 61 onto an endless, preferably the surface-hardened fibrous web, by means of a porous conveyor belt 62. 2 on rollers 25 a, 25 b, 26 α and 26 b revolving, end and 3 illustrated conveyor belts 37 and 62, loose conveyor belts 24 and 25 can be provided by a with hot or vacuum chambers, air heated to the desired temperature, 20 which out of the hardening furnace 23 which is conventional in the containers 36 and 61 with binding. The waves 29 medium impregnated fibers on the conveyor belts 37 and 30 of the rollers 25 a, 25 b, 26 a and 26 b are in and 62 suck. The conveyor belt 62 is supported by whale suitable frames 27 and 28. The distance zen 63 driven and at the outlet end of the container of the conveyor belts 24 and 25 is chosen so that at 61 under a pressure roller 64 for mixing and hardening of the partially hardened fiber web 45 consolidation of fibers and binders through a product of the desired thickness, for example.

19 mm is obtained. The temperature and the temperature in the illustrated embodiment is the While in the heating furnace, the Bedin fiber fleece mentioned must first pass through on rollers 68 and 69 conditions correspond. After leaving the hard circulating conveyor belts 66 and 67 through a Oven 23, the cured fiber fleece is guided by means of 30 pre-curing oven 65 and in this on a counter-one further endless conveyor belt 32, which is preferably not less thick than the final thickness a roller 33 is driven on a shaft 34, compressed and heated by heating air over its entire thickness further processing stages, for example cutting pre-hardened to a certain extent.

den, painting, etc. supplied. When leaving the on the rollers 68 and 69 um-Bei the modified 35 running conveyor belts 66 and 67 shown in FIG. 2 can through Embodiment of a device for through-spray heads 70 additional binders, auxiliaries tion of the method according to the invention are the od for decorative treatment of the surface. Fibers generated by a centrifugal device 35 onto the uniformly pre-hardened fibrous web a molding device 36 with binding agent.

mixed and by a 40 moved by rollers 38. The spray heads can be arranged on a frame 71 endless conveyor belt 37 under a pressure roller 39, which passes through one or more arrangements and thereby thoroughly mixes them. of heated rollers 72 and 73, which are rotatably mounted on the uncured, resilient fiber shafts 74 and 75 obtained in this way. Instead of this, the layer essentially corresponds to the state on, an arrangement with an endless conveying point 16 of FIG. 1 can also be used here, but as a result of the effect 45 bands of the type described are used, the roller 39 being more uniform. In this stage, the uniformly pre-cured layer is transferred to a nonwoven fabric driven by rollers 41 on a compared to both the endless conveyor belt 40 and can pass through to the end product, as well as to that in the last curing oven from above and / or below the thickness achieved is compacted smaller thickness. Sufficient heat is supplied through the porous conveyor belt 40 with the aid of heating 50 to pre-cure the surface lamps 42. When leaving the area, however, the fleece core does not harden.
Conveyor belt 40 can then be applied to the fiber layer, then the pre-cured and upper, for example by spray heads 43, additional surface-cured fiber fleece by means of binders on rollers 79, auxiliaries to improve the surface and 80 circulating endless conveyor belts 77 and 78 surface quality or fiber-binder mix 55 through a curing oven 76 guided on a frame 81, conditions are applied. The frame 44 contains one or more arrangements of heated rollers 45 and 46, of which at least one, preferably the upper one, including the Method according to the invention by means of the position of the roller gap vertically displaceably is supported by an essentially consisting of two plates. In each arrangement, at least one mold is to be carried out, with at least one of the plates being roller in the manner described with reference to FIGS. 1 is heated. The plates are then heated to each other in the manner specified. approximates a distance which is less than the final thickness exiting from the rollers 45 and 46 and is also less than the completely surface-hardened fiber fleece, through 65-digen curing of a product, the desired one mounted on rollers 48 in the frame 49, endless thickness required spacing. The duration of this conveyor belt and the subsequent endless conveyor closed position of the plates and their temperature bands 51 and 52 passed through the curing oven 50. are chosen so that no complete hardening

tion of the fleece core occurs. The panels are then cut to one of the desired final thicknesses Fiber fleece corresponding distance apart and that is elastic to this thickness cured expanding fleece.

A typical fiber fleece of the type according to the invention has, for example, a thickness of 19 mm, a specific weight of 0.064 g / cm ³ and a weight per unit area of approximately 1200 g / m ² . Before passing through the heated rollers, the thickness of the fiber layer used to produce such fibrous webs is about 250 mm, the distance between the rollers is about 6.3 mm and the distance between the conveyor belts in the curing oven is about 19 mm.

In a comparative experiment, uncured glass fiber fleeces impregnated with phenolic resin were cured in a press with electrically heated plates. In a first experiment, the distance between the plates of the press was set to 19 mm and the glass fiber fleece was cured throughout in one step. In a second test corresponding to the method according to the invention, the plates of the press were brought together at a distance of about 6.3 mm for about 10 seconds and then held at a distance of about 19 mm for a further 2 minutes. The cured glass fiber fleeces obtained in these tests with a total of eight test pieces had a thickness of 19 mm and a density of 0.064 g / cm ³ after curing. The test pieces were each sprayed with a customary white ceiling paint while adhering to certain layer thicknesses and, after they had dried, the reflection was measured. The results of these tests are summarized in the table below. For comparison, data are given for a product that has been on the market for several years under the name "Ultracoustic Travertine". In this case, the listed coating weight corresponds to the nominal weight, which can vary by 2 g up or down. The specified numerical value for the reflection corresponds to the minimum permitted, whereby products with low reflection are automatically rejected during the test. This product is made from continuously running glass fibers and a dry phenolic resin, while the product made by the process according to the invention was made from glass fibers produced in a centrifugal device and a liquid phenolic resin. Both products were brown before painting. A pigmented aqueous dispersion of an acrylic resin was used as the paint. The reflection measurement was carried out with a Gardner color difference measuring device. The results of these tests are summarized in the table below.

Dry weight Nonwoven fabric reflection the paint layer
g / m2 according to the invention 82.1 0.86 single stage hardened 71.8 1.07 according to the invention 88.3 1.50 single stage hardened 81.4 1.61 according to the invention 88.2 1.61 single stage hardened 82.5 1.72 according to the invention 89.3 3.01 single stage hardened 87.9 3.33 Ultracoustic travertine 80.0 minimum 2.69 nominal

These comparative measurements show that the nonwovens produced according to the invention have better reflection than the single-stage hardened nonwovens. This effect is due to the fact that as a result the production according to the invention, the fiber density on the surface is greater and thus a smoother Surface structure results.

The disclosed devices for the manufacture of nonwovens are only affected by patent protection insofar as they be used to carry out the method according to the invention.

Claims (1)

Claim: Process for the production of binder-strengthened binders consisting of a uniform fiber material Fibrous webs that have at least one surface with a greater fiber density than in the Core of the fleece, and in which a thermosetting binder for bonding the fleece is used, characterized in that the starting fleece, which is uniformly equipped with the binding agent, by thermal conduction and one for binder hardening in the heat supply area under the application of pressure Sufficient heat is supplied so that the material to be treated is then relieved of pressure and that thereupon the binder of the pressure-relieved material to be treated by further supply of heat is fully cured. References considered: U.S. Patent No. 3,025,197. 1 sheet of drawings 809 559/312 5.68 © Bundesdruckerei Berlin