DE3012910A1 - METHOD FOR PRODUCING MULTI-LAYER WOOD PANELS FOR DOORS, PARTITIONS AND THE LIKE, WHICH ARE RESISTANT TO STRONG MECHANICAL STRESSES, AND PANELS PRODUCED BY THE METHOD - Google Patents

Description

Dipi.-I ng. H. MITSCHERLICH Λ. D-8000 M DNCHEN 22

Dipl.-Ing. K. GUNSCHMANN * Steinsdorfstrasse 10

Dr. rer. not. W. KÖRBER * (089) «29 6684

Dipi.-Ing. j.scHMiDT-EVERS Jv I ^ yI U

PATENT LAWYERS

April 2, 198ο

SCIA SOCIETA COMPENSATI
IMPIALLACCIATURE ED AFFINI SpA
2, Via Mangili

Milan / Italy

Process for the production of multilayer wood panels For doors, partitions and the like. Which are resistant to strong mechanical loads, as well as after Method made panels

The invention relates to a method for the production of multilayer wood panels, in particular for doors, Partition walls and the like, which are resistant to strong mechanical stresses, for example like them in the event of attempted break-ins (burglar-proof doors and walls) or against the penetration of projectiles that be shot at a short distance (bulletproof doors and walls). The invention is also applicable to doors, Walls and the like directed when they are obtained with the aid of panels produced by the method according to the invention will.

It is known that for the production of a door or a partition made of wood with resistance to break-in attempts or that are downright impenetrable for projectiles, even if they are shot down at a short distance be, one has hitherto proceeded to equip them with thick armor, generally through a

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or a plurality of metal plates of appropriate thickness is formed. The well-known negative aspects of doors or partitions obtained in this way, for example the increase in weight of each finished product, the poor handling properties, the increased costs of production and its implementation, The limited workability and malleability of the metallic armor compared to wood have the production limited by bullet-proof and burglar-proof doors and walls of standardized dimensions or shapes, which also its field of application has been limited. Another limitation is the unfavorable appearance of the finished goods, if they are manufactured using the aforementioned technique. There is therefore a high and unsatisfied need for doors, partitions, etc., with resistance to break-ins and floors, which are at least comparable with doors and walls that are armored according to the known method, however are advantageous in terms of weight, manipulability, workability and formability such as in the case of wood, so that the aforementioned disadvantages are overcome.

A first condition to satisfy the aforementioned requirement, consists in using a wooden board that is able to withstand a projectile, too when fired at a short range. In other words, this wood board requires that all the kinetic energy of the projectile is converted into mechanical work to do part of the Deform plate extending over a portion of less length than the thickness.

A second condition is to keep the thickness of such a wooden panel within limits that are economical.

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economically unä technical with regard to the makes (doors, partitions, etc.) which are made with them should be acceptable.

The solution to the technical problem that emerges from the above explanations consists in the manufacture a wooden board with several layers, with which reinforcement layers are interposed, wherein each reinforcement layer has a stiffness value which is higher than that which is adjacent Wood layers is known.

This differentiated "oifigkeit" from layer to layer in a multi-layer wood panel is such that the reinforcement layer can initially bend on the following wood layer of lower rigidity when it is impacted by the projectile, which is why the concentrated force exerted on the reinforcement layer by the projectile is distributed over a larger surface of the subsequent wood layer, which results in a reduction in the specific forces. This "mechanism" is repeated when the projectile hits the subsequent reinforcement layers in the multilayer panel. As a result, the kinetic energy initially possessed by the projectile is rapidly canceled because of its conversion into work exerted to deform the layers, in particular to deform the wood layers, of which ever larger surface parts due to the presence of the reinforcement layers be affected by increased rigidity.

The process of interposing layers of wood and layers of reinforcement, for example, by fibers

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Formed by suitable mechanical features impregnated with suitable resins in the field of manufacturing, for example, plywood and the like, or panels of reduced thickness already known for seats or landings or cladding that are resistant to environmental influences are. However, it is also known that products of this type do not have effective mechanical resistance against attempted break-ins and all the less against projectiles that are fired at a short distance, to have. In addition, the multilayer panels obtained with the known technique do not have any the desired properties in terms of manipulability and workability like a block of wood.

Attempts to use the mentioned known technique, layers of wood and layers of reinforcement between each other arranging to obtain multilayer panels of very great thickness have resulted in panels which except for the lack of machinability and malleability when they have bullet security tests and burglary security tests give the same lack of resistance properties as the multilayered ones Slabs of thinner thickness. One explanation for this negative behavior is that with the temperature and pressure conditions proposed by the known technique to the number of To polymerize and solidify wood and reinforcement layers, the wood layers an extensive Bakelization experience what causes a constant increase in their degree of rigidity.

The invention relates to a process for the production of panels made of wood with several reinforcement layers, which are workable and malleable like a block of wood for

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-. Q -

Manufacture of doors, partitions and the like, which are bulletproof and burglar-proof, which process differs through the following successive phases:

- Impregnation of reinforcing fibers chosen between jute fibers, polyester fibers and polyamide fibers are, with a thermosetting resin between urea resins, melamine resins and their Mixtures are selected, the possible moisture content being regulated to values that are not are higher than 12 wt%;

- the forming of a stack made up of a number of layers of wood with a thickness between 1.0 and 1.6 mm is formed, between which layers the reinforcing fibers impregnated with the aforementioned resin alternate;

the stack at a temperature of 90 ° C to 130 ° C and a pressure of 83.263 N £ n ² to 259.807 N / xn ² with consequent simultaneous reticulation of the resin and adhesion of each layer of reinforcing fiber and reticular resin to the adjacent wood layers and prevention of penetration a Bakelizing effect in the wood layers.

The invention also relates to a monolithic wood panel with several layers that resist strong mechanical stresses are resistant, whereby it differs in that it is through a Number of alternating layers of wood with a thickness between 1.0 mm and 1.6 mm is formed as well as by Layers of reinforcing fibers sandwiched between jute fibers,

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Polyester fibers and polyamide fibers are selected and are impregnated with a thermosetting resin consisting of urea resins, melamine resins and mixtures thereof is selected.

Further features and advantages of the invention emerge from the exemplary embodiments described below of a method according to the invention and the test results obtained with multilayer wood panels were, in connection with the accompanying single drawing in a perspective view and partly in Section of a plate according to the invention.

Example I.

On the lower plate of a hydraulic press, which was equipped with plates that were controlled with means Were provided with heating, a stack was formed, which was formed by 17 layers of beech wood, which with 16 layers of reinforcing fiber impregnated with resin alternated.

In particular, each layer of beech wood had dimensions of 440 430 χ 1.4 mm, while each reinforcement layer was formed by three mats made of polyester resin fibers impregnated with melamine resin. Every mat had a thickness of about 0.50 mm. The moisture content of each polyester resin fiber mat impregnated with melamine resin was 9% by weight.

By operating the press, the aforementioned stack

2 simultaneously a pressure of 176.526 N / cm and one Subject to temperature of 104 ° C. These pressure and temperature

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temperature conditions were maintained for a period of 1 hour, which is a degree of reticulation or polymerization of the resin, so that the reinforcement layer at the end of the treatment mentioned Rockwell hardness R 75 (ASTM-D 785 - mean value from 6 samples).

When the press was opened it became a monolithic plate with a thickness of 50 mm, a total weight of 12 kg and a specific weight of 1.19 kg / dm.

This panel was machinable with woodworking tools much like a block of beech wood.

Below are the exam results on resilience reports against the penetration of projectiles, which tests with that described in Example 1 Method obtained plate were carried out.

Such a plate was rigidly attached to a metallic support and the projectiles were removed from a distance Fired from 2 m with a trajectory perpendicular to the surface of the plate.

Environmental conditions:

- Temperature: 20 ° C

- relative humidity: 65%

- Air pressure: 739 mm Hg.

a) Uberti caliber 357 Magnum revolver - length of the barrel; 190 mm - RWS Geco cartridge - armored with a pointed arch of conical shape of 10.2 g. the

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kinetic energy of the projectile at 2 m = 760 joules. There were 3 shots in the crown an isosceles triangle with a base of 32 mm and a leg length of 25 mm. All floors have been stopped. The impact of the third floor has the break of the last layer of beech veneer and a slight deformation of the back surface of the plate had.

b) Uberti revolver, caliber 44, Remington Magnum length barrel: 190 mm - WESTERN cartridge fitted with a 15.5 g Gas Check Lubaloy bullet. The kinetic energy of the projectile was at 2 m = 1500 joules. There were 3 shots in the crown an equilateral triangle with a side of 65 mm fired. All floors were stopped. The back of the plate had deformed considerably at the points where the projectiles were impacted the last layer of beech wood veneer cracked.

c) Franchi automatic rifle, caliber 12 - cartridge Gevelot, equipped with a BRENNEKE projectile made of lead of 27 g - energy of the projectile at a distance of 2 m = 2200 joules. There were 4 shots in the vertex of a square with a side length of Fired 75mm. Result of the test: same as for test b).

From the results obtained it can be seen how the wooden board according to the invention is remarkable and surprising Has resistance properties to the penetration of projectiles fired at a short distance will.

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Of course, such a plate can also be used to advantage for the production of burglar-proof doors.

Example 2

The procedure of Example 1 was repeated with the exception that the polyester fiber mats were impregnated with a urea resin. In this case, the temperature and pressure conditions were 112 ° C and 205.947 N / cm ² , respectively. These temperature and pressure values were maintained for one hour.

When the press was opened it became a monolithic plate get which, after doing the same tests for resistance to penetration of projectiles gave the same optimal results.

Example 3

The procedure of Example 1 was exactly repeated with the exception that the polyester fibers with a mixture of Urea resin and melamine resin were impregnated. In this The trap was the temperature and pressure conditions that the stack of wood layers and reinforcement layers had was subjected to 130 ° C and 196.14 N / cm. These pressure and temperature conditions were for the duration of a Maintain hour.

When the press was opened, a monolithic plate came with it 45 mm thick, which, according to the tests for resistance to penetration,

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penetrating projectiles, showing results exactly the same as those for the wooden panel Example 1 were given.

The wood panels obtained by the methods of Examples 2 and 3 were also made with woodworking tools workable with the same ease with which a block of beech wood can be worked.

Example 4

The procedures and Examples 1-3 were repeated except that the reinforcing fiber mats were through Jute fibers and polyamide fibers were formed.

In all cases, monolithic wood panels were obtained which were workable with woodworking tools and exhibited essentially the same missile penetration resistance as the previous ones for the wooden panels according to Example 1 was given.

The procedure according to the previous examples has been carried out for a number of stacks of wood layers and reinforcement layers repeated like the stacks used in Examples 1 to 5 with the exception that the printing conditions were gradually reduced over the range of 196.14 N / cm to 83.263 N / cm, while the temperature was changed in the range of 90 ° C to 130 ° C.

In this way, monolithic wood panels have always been obtained, which can be easily worked with woodworking tools tests for resistance

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ability to withstand penetration by projectiles and gradually decreasing values of resilience. However, all of these wooden panels retained remarkable and valuable properties in terms of resistance to burglary.

Example 5

The procedures of Examples 1 to 4 were repeated except that prior to forming the stack at least an additional layer under more uniform Distribution with abrasive particles sprinkled formed by metal grit.

In all cases, monolithic plates were obtained from the press, which in addition to the advantages of resistance against strong mechanical stresses are invulnerable by common burglary tools such as hand saws, proven, but maintained good machinability with normal woodworking tools, including widia blades.

It is important to emphasize that the monolithic wood panels obtained by the method according to the invention have shown considerable fire resistance, which are always found to be consistent with the values have proven in the current safety regulations against the risk of fire, especially when using of glass or jute fibers made with melamine resin impregnated are indicated.

In the accompanying drawing, 1 generally denotes a multilayer wood panel, which is represented by a number

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Beech wood layers are formed, all of which are designated with 2 and have a thickness of 1.4 mm and with Alternate reinforcement layers, all labeled 3 and each 1.5 mm thick. the Layers 3 are impregnated by a plurality of mats, generally designated 4, made of polyester resin fibers with melamine resin. Finely divided abrasive particles 5 are advantageously provided, which are formed by a metal shot and are contained in one of the reinforcement layers.

Patent attorney

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Claims (6)

Dipl.-Ing. H. MITSCHERUCH D-8000 MDNCHEN 22 Dipl. -Ing. K. GUNSCHMANN Steinsdorfstrasse 10 Dr. re r. η at.W. KÖRBER ^ ^ W ? 0Q Dipl.-Ing. J. SCHMIDT-EVERS ^ " PATENT LAWYERS April 2, 198o SCIA SOCIETA COMPENSATI
IMPIALLACCIATURE ED AFFINI SpA
2, Via Mangili Milan / Italy Expectations : / l.l process for the production of multilayer wooden panels, especially for doors, partitions and the like, which are resistant to strong mechanical loads are, characterized in that reinforcing fibers made of jute fibers, polyester fibers, Polyamide fibers and the like are impregnated with a thermosetting resin, which is made from urea resin, melamine resins, and their mixtures is selected, whereby the possible moisture content is regulated to values, which are not higher than 12% by weight, a stack is formed which is formed by a number of layers of wood with a thickness between 1.0 mm and 1.6 mm is formed with layers of the above alternate reinforcing fibers impregnated with the aforesaid resin; the stack is exposed to a temperature of 90 ° C. to 130 ° C. and a pressure of 88.263 N / cm ² to 259.807 N / cm ² with the following simultaneous reticulation 030043/0742 ORlGlWAl of the mentioned resin and adhesion of each reinforcing fiber layer and reticular resin to the adjacent ones Wood layers preventing the penetration of the Bakelizing effect into the wood layers. 2. The method according to claim 1 for the production of multi-layer wood panels for bulletproof doors, partitions and the like., Characterized in that the said stack is formed by a number of wood layers which are covered with layers ^ of reinforcing fibers which are impregnated with the resin mentioned, alternate, and a temperature of 90 ° C to 130 C and a pressure of 196.14 to 259.307 N / cm ² for a period of time between 50 and 65 minutes. 3. The method according to claims 1 and 2 for the production of multilayer burglar-proof wooden panels, thereby characterized in that in front of the stacks at least one layer of the reinforcing fibers mentioned, the are impregnated with said resin, evenly distributed with abrasive particles is sprinkled. 030043/0742 4. Multi-layer plate for bullet-proof and tamper-proof Doors and partition walls produced by the method according to claim 1, characterized by a number Layers of wood alternating with layers of reinforcing fibers, which are between glass fibers, polyester fibers, Polyamide fibers, jute fibers and the like are selected and impregnated with a thermosetting resin are made from urea resins, melamine resins and mixtures thereof is selected. 5. Bulletproof plate produced by a method according to claim 2, characterized by a number Layers of wood covered with layers of reinforcing fibers alternate which between polyester fibers and polyamide fibers, jute fibers and the like. Chosen and with a thermosetting resin is impregnated between urea resins, melamine resins and their mixtures is selected. 6. Burglar-proof panel manufactured according to a process according to claim 3, characterized by a number of wood layers with layers of reinforcing fibers alternate between glass fibers, polyester fibers, polyamide fibers, jute fibers and the like. are selected and impregnated with a thermosetting resin chosen between urea resins, melamine resins and mixtures thereof is selected, at least one of the fiber layers in a uniform distribution contains abrasive particles. 030043/0742