DE2606924C3 - Process for the production of plate-shaped structural elements that can withstand shear loads - Google Patents

Description

40

The invention relates to a method according to the preamble of claim 1. -ei

Such a method is known from GB-PS 13 81 637 and DE-PS 9 49 524. In the method according to DE-PS, a fiberboard or the like as a cover plate is secured against buckling and bulging as a latticework by combining with interconnected stiffeners. The fastening of the citterworks to the plate is carried out in planar fashion by means of gluing. The stiffeners can be covered with panels on both sides. As is the case with gluing in detail, the v> publication cannot be found.

In the process known from GB-PS, large plates of the type grazed after the process to be produced according to the invention, in a the plate receiving device using a hardening adhesive and applying pressure manufactured. A stack of components is enclosed in a chamber, and: the chamber becomes put under vacuum being by a corresponding movable formation of at least one wall of the chamber, the pressure difference between the negative pressure in the chamber and the atmospheric pressure gives the pressure required for proper bonding. The pressing devices are complex, and a relatively long residence time in the chamber is necessary.

Known cover plates made of chipboard or the like usually have a flexural elasticity module of about 100,000 kg / cm ² and below. The term "flexural modulus of elasticity" used here denotes a value for the section modulus of resistance that depends on the material properties and dimensions in relation to the zero line for the tension and compression side. The lower the flexural modulus of elasticity, the easier it is for the plates to bend.

The invention is based on the object of providing a method as described in the preamble of claim 1 described type so that for gluing the latticework with the cover plate or the Cover plates of a component do not have any special facilities for applying the pressure or for Clamping are required.

This object is achieved according to the invention by what is contained in the characterizing part of claim 1 Features solved.

It is then used an adhesive that hardens substantially completely dimensionally stable, i.e. the shows no shrinkage when hardening, and on the other hand, the adhesive is applied in an amount which is sufficient to in any case, even without applying additional pressure, all differences in the Height of the gap formed by loosely placing the cover plate on the edge surfaces of the latticework compensate. When the cover plate is put on, the adhesive is displaced by its own weight to such an extent that that a complete gap filling is achieved, this gap filling due to the lack of shrinkage of the adhesive even after it has hardened. This makes it possible to use the adhesive surfaces on the cover plates and on the edge surfaces of the bars forming the bars, to be left practically in the delivery condition, d. H. not to be processed or only to a small extent. The glue can be applied as a strand or 1,, teardrop shape Adhesive surfaces are applied, whereby he due to the relatively large adhesive gap height through the only of the The pressure exerted by the weight of the cover plate is distributed by itself over the entire adhesive surface. It is omitted also all special devices to exert a contact pressure η and this contact pressure up to Maintain curing of the adhesive. Only that caused by the dead weight of the is under "pressureless" Understand the pressure generated by the cover plates.

In the method according to the invention, the accuracy in cutting the parts is not critical, and it is easy to apply the adhesive and monitor the joining of the elements. It there are essentially no connecting surfaces with a larger gap than the one required Strength can be bridged by the gap filling adhesive.

The components produced by this process have the same physical properties as Components that are produced by previously known methods, such. B. by nailing (DE-PS 9 49 524) or gluing under pressure (GB-PS 13 81 637) Von Plattenmateriaiieri mt a wooden lattice,

The two processes according to the invention used resorcinol or resorcinol / phenol resin, based on formaldehyde, contain fillers known per se,% B. Kokosschäienmehi and / or colloidal silica

re. A suitable solids content is 5 to 60 % By weight, preferably 10 to 25% by weight, based on the composition. A high solids content is preferred.

Because the adhesive has thixotropic properties it is easy to use and stable in its Shape before and during application. This property is known by adding "thixotropic agents, such as colloidal silica, causes. As a preferred range of thixotropy was the following according to the Brookfield RVT rotary viscometer, sp.7, measured area determined:

At 1 rpm 20,000 to 2,000,000 cP,

5 rpm 55,000 to 550,000 cP and
50 rpm 10,000 to 100,000 cps.

The amount of adhesive applied, e.g. B. the dimension of the adhesive strand applied is important for achieving a well-filled adhesive gap. The diameter of a strand should be Exceed 2 mm and are preferably in a range from 3 to 10 mm. If the surface is too rough Adhesive surfaces are preferably laid two strands to ensure good distribution and gap filling to ensure.

If the adhesive is cold-setting, it will harden in a not too long time at a temperature below 35 ° C.

A material is used for the latticework that changes approximately uniformly in dimensions in the Χ, Y and Z directions with changes in humidity and temperature - and composite materials.

The adhesive can be applied manually or automatically, e.g. B. with the help of a gun, are applied in the Adhesive and hardener are mixed automatically in appropriate proportions or with the adhesive and hardener must be applied separately.

The following is a description of exemplary embodiments of the invention with reference to the drawings.

In the drawings shows

F i g. 1 is a plan view of a gilter factory,

F i g. 2-9 show a method for producing plate-shaped components.

The latticework according to Fig. 1 consists of a number of parallel webs 1. perpendicular to these are cross webs 2, 3 at the ends or between them intended.

To connect the latticework, the webs are held in place, e.g. B. with the help of fittings. Internal connections, stop pieces nailed to a support or point fastening.

The spaces between the latticework can be covered with insulation in the form of glass or mineral fiber panels, or directly with plastic foam be filled. Any reinforcement that may be required can also be provided in these spaces be.

A preferred procedure will now be described with reference to FIGS. 2 to 9 explained.

After creating the latticework 11 is on a level support 14 deposited. Use glue on the edge surfaces of the webs. Help of a pistol 15 (Fig, 2) applied, and a cover plate 12 on it placed (Fig. 3). This process is accomplished by putting on of further ElemenlexfsA repeated many times until a stack 17 (Fig. 4) is created. An additional plate is made if necessary placed on top of the last element to improve the contact When the adhesive in the gaps has solidified sufficiently, the elements are rotated 180 ° (Fig. 5) rotated Then insulating material 16 is installed if necessary (Fig. 6). Then glue is applied to each Edge surfaces of the webs applied to the other sides of the latticework (Fig.7), and one more each

ίο Cover plate 13 placed (Fig. 8) until a stack of completed elements is created (Fig. 9).

example 1

A latticework of chipboard webs was put together by fixing with one edge in a holder and connected with the help of some brackets or a hot melt glue. In the An insulating material was incorporated into the latticework. An adhesive having the following composition was made applied to the edge surfaces of the latticework:

Resorcinol phenolic resin

(Dry content about 70%) 100 parts by weight

Formalin solution (37%) 25 parts by weight

Coconut shell flour 25 parts by weight

A chipboard was placed as a cover plate on the adhesive-coated edges and secured against shifting with the help of some clamps.This construction was turned over and strands of adhesive were applied to the opposite edges of the latticework and then another chipboard was laid on top of a number of elements put on top of each other and stored for about 3 hours. The bonded edge surfaces then had a shear strength of at least 15 kp / cm ² .

Example 2

A latticework of webs from a 19 mn. thick Plywood or chipboard are held together and attached to a surface of 10 mm thick chipboard that ajf rests on a flat surface Adhesive layer provided which, when the cover plate is placed, is at least 0.5 mm thick of a thermosetting Resorcinol-based resin forms which has the property that it completely fills the gap afterwards a chipboard has been placed as a cover plate on the upper side of the frame

The adhesive is only used to harden by the compressive force due to the weight of the topmost chipboard exposed. The adhesive used has the following composition:

Resorcinol resin

(Dry content about 60%) 100 parts by weight

Formalin solution (37%) 25 parts by weight

Coconut shell flour 25 parts by weight

The cover plates were preheated to a panel heater at 14O ⁰ C "Min long before factory Gittei-on were launched = Shear strength was determined at different time intervals highlighting the following results were obtained.:

3 minutes after connection

5 minutes after the connection has been established

10 minutes after connection

20 minutes after connection

2.5 kgf / cm ²
6 kgf / cm ²
13 kgf / cm ²
23 kgf / cm ²

The hardening of the Adhesive can be accelerated so that the elements could be transported or handled quickly.

After less than 5 minutes, the strength was sufficient Transport, and after 10 minutes the strength was in the range required for the finished construction is.

When determining the shear strength, fractures always occurred in the material of the cover plate and not in the Connection between edge or web and adhesive.

sis with the following composition used:

Example 3

A number of laboratory tests have been carried out with different combinations of materials when gluing the structural elements, ie with different decking materials, different latticework materials and with different dimensions. Various types of plywood, fiberboard, and particle board were used as the facing materials, and the same materials and wood were used as the lattice material. The thickness of the materials varied from 10 to 20 mm. An adhesive on resorcinol-phenolba-resorcinol-phenolic resin
(Dry content about 50%)
Formalm solution (37 ° / oJ
Coconut shell flour
pH

loo weight parts
25 parts by weight
21 parts by weight
7.5 to 8.0

Apart from the weight of the plates themselves, no additional compressive force was applied. The results are summarized in the table below; These results show that cover plates with a relatively low flexural rigidity, ie with a flexural modulus of no more than 100,000 kg / cm ² , preferably less than 50,000 kg / cm ² , are required in the method according to the invention, if none additional compressive force is applied.

The materials used for the cover plates and latticework were construction materials according to Swedish standards for load-bearing building materials.

The components would be loaded until they break and it was determined at which point of the connection the edge surface of the web-adhesive layer-cover plate the break occurred. In the following table, under the The “Behavior” column indicates what percentage of the fracture surface was in the material of the cover plate.

Table according to example 3

Cover plates the same Bicge E module Latticework behavior Usability of the ι the same Component 1 10 mm chipboard 32,000 kgf / cm ² 10 mm chipboard 100% breakage excellent the same in the chipboard the same 12 mm cardboard the same the same the same 10 mm plywood the same the same plate 1 the same 20 mm redwood 50-75% breakage partly worse I. in the chipboard Contact as a result of the I. Warpage of redwood I. 12 mm cardboard 20000 kgf / cm ² 10 mm chipboard 100% breakage excellent in the cardboard I. the same 12 mm cardboard the same the same 1 the same 10 mm plywood the same the same plate I. the same 20 mm redwood the same sometimes worse Contact P. 10 mm plywood 100,000 kgf / cm ² 10 mm chipboard 50-75% breakage partly worse ! ^ atte in the plywood sheet Contact due to delay I. the plywood sheet i 12 mm building board the same the same i 10 mm plywood the same the same plate 20 mm redwood the same the same and of redwood

Example 4

For insulated, load-bearing structural elements with dimensions of 8 χ 2 m, which are intended for external walls, a chipboard with the dimensions 8x2 ^ m and a thickness of 12 mm was used as the cover plate Lengths were different. The same adhesive was used as in Example 2. Glass fiber wool with a thickness of 16.4 cm was used as the insulating material. The structure corresponds to that of FIG. That

Latticework was 20 mm within the outer edges of the cover plates, and the distance between the webs of the Lattice work was 50 cm.

A chipboard was placed on a flat, vertically adjustable Tiso'li, with the bendable Chipboard lay tightly on the table. In order to form a latticework as shown in FIG short attachment pieces 4 (Fig. 2) with dimensions Nailed 2 χ 2 χ 1.5 cm to the chipboard according to the latticework to be created. Öef distance between the paired pieces was about 80 cm, and the distance between the pieces in a pair was 12 mm, before assembly a stick of adhesive about 5 mm high was placed on the Applied edge surface of the lattice bars and placed the cover plate. At no connection point A gap of more than 1.5 mm was found between the latticework and the cover plate.

After turning the element, glass fiber wool was used and a diffusion wall is installed in the box-shaped structure thus prepared. Strands of the same Adhesive was applied to the edge surfaces at the top of the latticework, and then the upper cover plate would be put on.

The element created in this way formed a stack with five other elements. A chipboard of 22 mm with the same dimensions as the cover plates was placed on top of the stack. Despite one just through the dead weight exerted pressure force and despite the large dimensions could connect well in all glutinous jars of the stack can be achieved, and hie glue joints larger than 1.2 mm were found. The stack was cured for 2 to 3 hours. After this time would be absolutely solid, non-creeping, weatherproof

iö connections available. There was a stiff and dense plaque-shaped building element, its length deviation was a maximum of ± 2 mm. The cover plates of the elements were completely undamaged, and after that Installation was no additional work, such as filling, etc., before painting or wallpapering necessary.

Samples were taken from the bonded elements and the shear strength of the layers in the cemented Kanierifiäcnen was measured up to 60 kp / Cffi ² on average. The required strength in the connection is a maximum of 15 kp / cm ² . Such a wall element was tested in detail, and after all of the bonded edge surfaces had broken open, a fracture surface was found, more than 90% of which was in the chipboard material.

For this purpose 3 sheets of drawings

Φ30 264/212

Claims (2)

Patent claims: 1. A process for the production of panel-shaped structural elements that can withstand shear loads, larger than 1.0 χ 2.5 m, from a latticework, on one or both sides of which a chipboard, fiberboard or plywood panel (cover panel) with a flexural modulus of elasticity is glued on below 100,000 kp / cm ² , and the webs of which are made of chipboard, fiberboard or plywood material, in which the adhesive is applied and the latticework and the cover plate (s) are placed on top of one another and glued, characterized in that a known, hardening resorcinol or resorcinol / phenolic resin is used, which by adding a filler is thixotropic, essentially retaining its shape and not shrinking much during curing, so that it is at least 0.5 mm thick and in such a thickness Amount is raised that between the edge surfaces of the webs and the cover plate occurring gaps are filled, and that the gluing of the latticework to the cover plate one side is carried out so that the application of the adhesive is carried out from above onto the edge surfaces of the webs, then the cover plate is placed and the adhesive is cured without pressure to the extent that the element can be handled, and that in the case of a cover plate on the second side it is one-sided coated member turned over and the second cover plate is applied in the same manner by laying on top of the adhesive with ve ^r 'ehenen edge surfaces on the upper side of the webs. 2. The method according to claim 1, characterized in that cover plates with a flexural modulus of elasticity below 50,000 kp / cm ² are used.