ES2352292A1 - Method for producing surfboard blanks from black cork - Google Patents

Abstract

This invention refers to a method for producing blanks whose main feature is that it makes it possible for them to be made 100% in black cork, achieving the specifications of lightness and resistance without the need for whatsoever chemical adhesive and also achieving other properties that are advantageous in comparison with traditional materials. This method dispenses with the longitudinal wooden core that currently needs to be attached to the blank and with any type of pollutant material in the manufacturing process, with evident benefits for the environment and for shapers, who are currently affected by the high toxicity of traditional materials. The procedure comprises four stages, which consist of grinding the virgin cork to a grain size of between 0.2 and 0.8 mm the addition of nitrogen in a high-pressure chamber the subsequent baking of the cork and its final removal from the mould as a shaped blank.

Description

Procedure for manufacturing cores of Surfboard in black cork.

Object of the invention

The present invention relates to process for manufacturing surfboard cores, known as blanks, made of totally natural cork, without the use of No type of synthetic material added to this.

The main feature of this invention It consists in enabling the manufacturing of the aforementioned cores in a totally traditional material such as cork, extracted from the cork oak bark and used for thousands of years by the man. Said material provides the core of the table with a series of advantageous properties that cannot be obtained with materials used today (foam, wood or plastics), being also a completely impactless alternative environmental, regarding the fact that the tree is not removed for harvesting of its bark nor is the use of any kind necessary of adhesive or chemical binder to form it, in contrast with the materials currently used, which incorporate various toxic substances that endanger health of workers and users and whose manufacturing process involves a Dangerous pollution for the environment.

An advantage derived from the greater resistance of the cork core result of the process is that it is not necessary the incorporation of a wooden soul as today is coming doing with the current materials. It is achieved in this way significantly simplify the manufacturing process and reduce manufacturing and assembly times, as well as a large reduction in energy needs

This document describes the different components of the process and the necessary treatments to perform to obtain a surfboard core with excellent properties for the practice of such sport, as It will be seen below.

Field of application of the invention

The present invention will have application within of the surfboard manufacturing industry and the like.

Background of the invention

The preparation of a surfboard today begins with the production of the core, called blank , in a material known as foam or epoxy and produced in an industry with the necessary production processes. These cores are subsequently sold to workshops and factories where they are molded by professionals, called shapers , who mold them properly and subsequently apply various layers of fiberglass that are fixed by means of a "glaze" of the set, which consists in the application of a resin diluted in petrochemical solvents. Finally it is sanded and polished to give the presentation finish.

The material known as foam is refers within the surfboard manufacturing industry to certain kinds of treated polyurethane or polystyrene foams chemically, and that emerged after World War II with the new materials that it introduced, replacing the tables of wood. This cheap alternative developed by Hobie Alter and Gordon "Grubby" Clark gave birth to a new era in the surfing, making it easy for a lot of people to access this sport. In parallel, the high polluting power of products employees in the manufacture of foam made surfing one of today's most polluting industries, to the point that in 2005 the main foam factory that produced and distributed 90% of the product worldwide, Clark Foam, was seen forced to close pressed by environmental laws North American However, the pressure exerted has not been translated in an effort of the manufacturers directed towards a process more clean, but the foam industry has simply moved to developing countries with less restrictive regulations and cheaper labor.

Shapers (modelers) use respirators to protect against dust and foam gases, which include volatile organic compounds such as 2,4-diisocyanate Toluene (2.4 TDI) which is a human carcinogen, according to the Agency International for Cancer Research (IARC) and that produces various effects on the body such as mucosal irritation, fatigue or trouble breathing This poses an obvious risk to the workers' health that would be desirable to eliminate at source, with a material to be molded that does not produce particles dangerous to the Being human or the environment.

On the other hand, foam turns out to be a material extremely fragile and deformable, so the incorporate a longitudinal wooden shaft that gives rigidity to the whole, called soul, which is an aggravation of the complexity of fabrication process.

For all the above, it would be desirable to appearance of a procedure that uses some material that had the advantages of foam (low density, elasticity and low price) and avoid the above mentioned inconveniences. The procedure object of the present memory not only achieves This, but provides added advantages, derived from the Excellent properties of cork.

The cork comes from the bark of the cork oak ( Quercus Suber ), an endemic tree of the western Mediterranean and that is what is called a climax tree, that is, the best adapted to its environment. In 1664, Robert Hooke discovered the cell and the cellular organization of organisms by observing a fragment of its cortex. In 1665 he devised a microscope and examined the cork, describing it as a tissue formed by small cells. Its chemical composition and anatomical structure make it a unique material in nature and that, despite the continuous advances of science and technology, and constant efforts in this regard, has not been able to imitate satisfactorily.

Black cork is a material obtained from of virgin granulated cork that after undergoing autoclave cooking exudes its own resin, called suberine, which agglutinates the grains and forms an agglomerate of excellent insulating properties, main reason for its use today. In the market it is possible find black cork in applications as an insulator for construction and anti-vibration, seals, being also used for insulation of thermal equipment and even spacecraft insulator. For each of these applications a different manufacturing process must be available depending on of the desired physical properties for the product.

The traditional treatment for the production of black cork begins with a crushed virgin cork up to a grain size between 2 and 10 mm, made in a hammer mill or star Then the granulate is cooked up to a temperature of about 400 ° C. This cooking makes the material expands, roasts and acquires its characteristic color and It also causes the cork to secrete a resin (called suberine) which agglutinates all grains naturally. By cooking in molds the different forms of tables are obtained. The structure Cork-shaped cell remains after the process of cooking, varying only in the increased size of said Cells In this way the excellent properties of the material.

It is not known by the holders of the present memory the existence of any process of treatment of black cork that manages to reach a final product with the physical properties necessary for use as a table core surf, which is confirmed in the absence of uses of black cork that require certain mechanical properties beyond the compressive strength, since, as this type of cork traditionally, the large size of the granules and the poor cohesion between them causes low resistance to tensile and torsion forces.

The present process describes the parameters necessary and appropriate treatments to obtain a surfboard core of that same black cork with excellent properties for the practice of said sport, as will be seen continuation. This process also solves the problems raised above, given that it becomes a ecological alternative compared to the previous methods of obtaining of blanks, with easy accessibility and that does not need any change in table modeling workshops, since the cores of cork would work with the same tools as traditional foam.

Explanation of the invention.

The process for manufacturing cores of Cork surfboards start with the cork granulate. How Raw material is possible to use very different qualities of cork, being able to use residual remains of other processes provided that these remains have not been contaminated with others materials such as wood or plastics.

The granulate is one of the most usual processes within the cork industry, although in the usual processes the black cork only granulates from 10 mm. For the development of the surfboard core is necessary to perform a ground to a grain size that will vary between 0.2 and 0.8 mm depending on the density and properties required by the use of the material, that is, the type of surfing said core is intended.

Cork is characterized by being formed of polyhedral cells, empty inside (approximately 80% of its volume is gas, especially nitrogen), closely linked each other, which make up the suberose tissue. However, this tissue has a discontinuous structure due to the presence of lenticels (pores) that radially cross the body of the cork in all its thickness. Lenticels are permeable to gases and liquids and allow to regulate the gaseous exchanges between the tissues alive from the trunk and the outside environment during the life of the tree.

Once the granulated cork is obtained at suitable size, the material will be introduced in a high chamber pressure, where nitrogen will be added until a pressure is reached enough to cause the penetration of said gas through the Lenticels After sufficient time for the nitrogen penetration has been homogeneous in all cells cork, we proceed to the introduction of the set in the autoclave for cooking

It is important to highlight that the camera step high pressure with nitrogen to the autoclave where the cooking has to be done without loss of the pressure at which it is submitting the cork, since it would cause the loss of a part of the gas contained in the cells. To do this, the high chamber pressure must be introduced into the autoclave, opening once ensure that the cooking pressure is equal to the pressure prearranged in the chamber.

The ground in such a fine grain size has as an objective to enable the resin, known as suberine, which will be naturally exuded through the lenticels in the cooking, distribute and coagulate completely and evenly the existing cork particles, thus providing the agglomerate, In addition to a good finish due to the uniformity of the surface In the end, great physical skills for the development of surfboard cores, as well as for the subsequent termination of the table, and for the practice of this sport.

The fact of having created an overpressure in the cork cells allows the application of higher temperatures in cooking, so that it is possible to increase the amount of suberine which will act as binder of the cork granulate, in addition to provide greater lightness to the material by increasing the content in lighter gases than the air they contain, in addition to increasing the volume of each of the cells.

In an advantageous embodiment, the high pressure chamber can fulfill a double function: in addition to serving for the initial nitrogen of the cork granulate, it can fulfill the mold functions once it is introduced into the autoclave. Depending on the technical specifications of each table, one or the other mold form must be used, and one or another size of granulate. Similarly, the nitrogen time as well as the proportions of gas used will be particular to each type of
table.

The autoclave process makes the cork expand, the microorganisms present disappear, and gives it the texture we usually know, in one color black. In this procedure the molds must be introduced in an autoclave that generates the necessary temperature from 420º to 450ºC, for 20/30 minutes. The heat applied to the cork causes it to exude its own resin and agglutinate, forming a compact block that, in applied mold function, will be arranged directly for your distribution or will go to the next molding process, in which finally the block is introduced for machining by numerical control machine or any other valid procedure For these functions. Thanks to the existence of high pressures in the autoclave is possible to obtain an amount of suberine such that they end up completely plugging a good part of the lenticels, preventing the gas contained inside the cells exhaust and finally providing a stable material with some lightness and strength properties that make it especially Suitable for making surfboard cores.

Advantageously it will be possible to use a high pressure chamber in which one or more of its walls are mobile phones, so that it is possible to vary the volume inside the camera, as well as obtaining various types of core with the same molding device.

Once cooking time has been reached necessary for proper segregation of the suberine contained in the cork cells should be allowed to cool the material with a progressive decrease in pressure inside the autoclave, so that a progressive adaptation of the material to the atmospheric conditions so that the internal stresses created in the material as a result of pressure and temperature.

A very important advantage derived from the Performing this procedure involves the permanence of a small number of lenticels that have not been hidden by the suberine in its exudation process. These lenticels act as micro suction cups thanks to the elastic properties of the cork, and will allow the final glaze of the table to be done with natural resins that with traditional means would be impossible to use due to its low cohesion with the blank material. With the present procedure is feasible the use of gomorresins of low resistance thanks to the permanent suction effort that is making the core itself on the outer layer, which fixes and provides an initial compression that will logically provide a extra resistance to the efforts of flexo-traction to which the core will be subjected during use

The cork, by its composition and structure is set as an ideal material for the manufacture of blanks, presenting among others the following properties:

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Lightness: it is because 88% of its Volume is air. This condition of lightness is indispensable for The current tables. It is one of the lightest materials that It exists, which gives it great buoyancy.

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Elasticity: it has a surprising elasticity. It involves a distribution of the force of the wave in a way more efficient and safe throughout the structure of the table, in addition to the possibility of adapting to any type of surf and surfer

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High coefficient of friction: the Cork surface is upholstered by microvents that allow Great adhesion and make it difficult to slip. This facilitates in greatly the correct fusion between the core and the resin that has of covering.

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high impermeability: the diffusion of liquids and gases through the cork It is very difficult and extremely slow. Unlike those foam blanks, the cork does not absorb water or deteriorate in contact with water.

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Aeroelasticity and damping of impacts: the area affected by deformation before an impact is it extends and is distributed by the adjacent zones, being the nucleus of Cork capable of absorbing and minimizing the turbulence of any wave as well as resist impacts or shocks.

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Poisson coefficient 0: when reduce cork volume in one direction does not occur deformation in the perpendicular direction, which reduces drastically the stress of the material when forced under conditions extreme

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Ease of handling: modifying the water content of the cork facilitates handling when it becomes more elastic As indicated above, a blank cork it would work exactly the same and with the same tools as one of foam.

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Low water content: the equilibrium moisture of the cork with the environment is usually 6%, making proliferation impossible of microorganisms and giving it great durability. In addition to clean and natural, cork core boards have a life Unlimited useful, unlike the current foam.

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Toxic: Cork does not have any type component that may be toxic to humans or environment. Its structure in the form of rounded cells makes that once sprayed is not harmful to the tracks respiratory, being easily removable by the body human.

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Biodegradable: in case of becoming residue, is totally biodegradable

The present invention also achieves agree on a sport like surfing, traditionally linked to very positive environmental values with the industry of supplies for this sport, paradoxically very polluting. He use of cork as raw material implies an energy expenditure around 500 times less than foam, not generating waste any contaminant

Given the wide variety of surf types Existing (surfing, windsurfing, bodyboarding, kitesurfing ...), the boards have of having very specific physical properties. To adapt to these needs, which may even vary according to the part of the same table in question, the possibility of using different sizes of granules within the preparation of the same blank, thus being able to achieve physical qualities needed in each core zone. For example, in one embodiment of the process a granulate may be arranged more coarse inside the core and leave a finer one for the outer coating, lowering the process.

It should be noted that although as it has been cited above it is not necessary to incorporate a soul of Longitudinal wood to obtain adequate strength of the nucleus, the present process allows to introduce this step of analogously to how it is being done today, that is, longitudinally cutting the core and gluing this soul with adhesives or resins. With the introduction of the wooden soul they obtain very high resistance of the core, which allow the use of the table in extreme conditions.

The described manufacturing process represents, Well, an innovative system that provides a product of characteristics unknown so far for that purpose, reasons that together with its practical utility, they provide it with sufficient foundation to obtain the privilege of exclusivity that is requested.

Preferred Embodiment of the Invention

The present invention is illustrated by the following example, for illustrative purposes only, with which It is not intended to limit its scope at all:

Starting from the acquisition of natural cork, without any previous treatment, which can be acquired directly on plates or as a leftover from some other manufacturing process, a cork core is manufactured for a longboard surfboard, of 2.80 meters long .. This type of board is designed to be propelled with small waves, so it will not be necessary to have a high impact resistance, although given the large length of the board a good resistance to stress will be necessary of flexo-traction. Therefore, a grain size of 0.4 mm is used that will allow the segregated suberine to be distributed in a way that allows some flexibility between the granules
United.

The process steps are as follows:

one.

Grinding. The initial material is introduced into a star mill capable of crushing it up reach a grain size of 0.4 mm. This cork powder then it will tip over the mold.

2.

Nitrogenous. The cork granules in a high pressure chamber, in which will introduce nitrogen in a gaseous state until a pressure is reached of about 3.5 Kg / cm2 for 1 hour. This camera will comply later the mold function, so you will have the form suitable for that purpose. Previously its surface will have been coated nonstick interior to prevent the suberine from adhering to the walls and the bottom, which would make it difficult to extract mold.

3.

Cooking. The mold / chamber is introduced in an autoclave where it will heat up to 450º during 20/30 minutes Once the pressure equivalent to that existing in the mold / chamber, it will open. In this period the cork exudes its resin itself, agglutinating and forming a compact body with the mold shape. In addition, the cell-shaped structure has been expanded, acquiring greater elasticity and the resin itself has plugged most of the lenticels, where he could escape the gas introduced into the cells.

Four.

Extraction. Once the cooking, the mold will be removed from the autoclave and allowed to cool to air to reach room temperature. Subsequently Remove the black cork core from the mold.

Once the cork core has been obtained, This is ready for distribution to workshops for completion final. As mentioned earlier, it is not necessary having a longitudinal wooden core to stiffen the core, since the material has sufficient rigidity on its own. From This way it is not necessary to cut the core into two parts to later unite them with the soul inside, greatly simplifying the manufacturing process.

For tables with different specifications it will be necessary, in addition to different thicknesses of granulate, the use of block molds that will later be machined with machine numerical control until obtaining the desired form, counting in this Case the process with one more step.

Describe sufficiently the nature of the The present invention, as well as the way of putting it into practice, is not considers it necessary to broaden his explanation so that any subject matter expert understands its scope and advantages that derive from it, stating that, within its essentiality, may be implemented in other forms of embodiment that differ in detail from that indicated by way of example, and which will also achieve the protection that collects as long as it does not alter, change or modify its principle fundamental.

Claims (4)

1. Procedure for manufacturing surfboard cores in cork, characterized by the fact that it consists of the following steps:

\ circ

Grinding, until reaching a size of grain between 0.2 and 0.8 mm.

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Nitrogenated, in a capable chamber of withstanding temperatures up to 450ºC and high pressures and that It will serve as a core mold.

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Introduction of the mold in autoclave and pressure equalization.

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Opening of the mold inside of the autoclave.

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Autoclaved in a temperature range between 420º-450ºC and 20 to 30 minutes of weather.

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Mold removal once cooled.

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Machining of the piece obtained in the parts that are necessary.

2. Procedure for manufacturing corkboard cores according to claim 1, characterized in that prior to the machining step of the piece obtained, the following step is included:

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Longitudinal cut of the core and glued to a wooden soul.

3. Method for manufacturing corkboard cores according to claim 1, characterized in that the chamber where the nitrogen is made and which will later serve as a mold, has one or several movable walls. 4. Method for manufacturing corkboard boards according to claims 1 to 3, characterized in that ground cork is used in various grain sizes, arranged in different areas of the mold.