ES2915328B2 - CONSTRUCTION PANEL OF FRUIT STONES AND MANUFACTURING PROCEDURE - Google Patents

Description

DESCRIPTION

CONSTRUCTION PANEL OF FRUIT STONES AND PROCEDURE OF

MANUFACTURING

field of invention

The present invention refers generally to the field of construction and, more specifically, to the field of acoustic conditioning in construction panels.

Background of the invention

In the field of construction, it is common to use panels as facings that are applied to walls and ceilings to improve their acoustic insulation characteristics. Among the products that can be found currently on the market, noteworthy are fir wood chip boards with cement, chipboard, high-density fiberboard or phenolic compacts.

The use of natural and sustainable products, therefore, with low environmental impact, is a trend in the world of construction. In addition, the demand for materials with thermal and acoustic conditioning properties is increasing.

Human beings have used fruit stones, like other woods, since ancient times. Its main use has been as fuel or biomass, although recently it has also been used for the manufacture of activated carbon and, after its crushing, in the manufacture of conglomerate boards.

However, currently there is not a wide variety of boards made of natural and sustainable products on the market, the most used being the agglomerates of wood chips with cement. It is necessary to expand the use of waste materials to improve environmental protection and increase the use of waste materials, offering products with higher added value.

Therefore, it would be desirable to provide a building panel composed of natural materials and, therefore, a panel that respects the environment. Furthermore, it would be desirable for such a panel to at least equal or even improve the acoustic conditioning properties obtained with panels currently known in the art.

Summary of the invention

In order to solve the above problems, according to a first aspect, the present invention provides a construction panel of fruit pits as an acoustic conditioning facing for walls and ceilings. The panel comprises uncrushed whole fruit pits (for example, olive, cherry, peach, plum, apricot, or any combination thereof), a resin matrix (for example, aggregate binder-type water-based resin), and a natural fiber base (eg jute, coconut, esparto grass and any combination thereof).

According to a second aspect, the present invention also provides a manufacturing process for a construction panel of fruit bones, comprising the steps of:

a) arranging natural fibers at the base of a mold;

b) mixing uncrushed whole fruit stones with a resin matrix;

c) pouring and vibrating the mixture obtained in stage b) over the natural fibers at the base of the mold;

d) smoothing the surface of bones by applying a small pressure;

e) leaving the mixture of stage b) to dry on the basis of natural fibers; and

f) demoulding a construction panel comprising uncrushed whole fruit stones, a resin matrix and a natural fiber base.

Brief description of the figures

The present invention will be better understood with reference to the following drawings which illustrate preferred embodiments of the invention, given by way of example, and which are not to be construed as limiting the invention in any way.

Figures 1 to 5 show graphs representing the acoustic absorption coefficient as a function of frequency of building panels according to various embodiments of the present invention, made from apricot kernels (figure 1), peach kernels (figure 2) , cherry pits (figure 3), olive pits (figure 4) and a combination of the four types of pits above (figure 5).

Detailed Description of the Preferred Embodiments

As mentioned above, the present invention refers to a construction panel composed of a matrix of resin and fruit pits with a base of natural fibers. The natural fiber base provides mechanical and insulation properties (not only acoustic, but also thermal, for example) to the panel. The panel maintains the physical and mechanical characteristics required by the applicable regulations (depending on use) and stands out for its good aesthetic, thermal and, especially, acoustic properties. Said panel can be applied as an interior lining for acoustic conditioning of vertical walls (walls) and horizontal walls (false ceiling). It can also be used as a board for the manufacture of sandwich panel in roofs.

The composition of the panels according to the present invention is based on resin with the addition of fruit pits taken from industrial waste and reinforced at its base with natural fibers bound by the resin to the pit panel.

The constitution process according to the preferred embodiment of the present invention consists, firstly, in placing a layer of natural fibers in a mold. On the other hand (simultaneously, before or after), the fruit stones are mixed with the resin matrix, until a compact, united and firm mass is achieved. The desired proportion must be applied to avoid excess or defect of matrix. Said mixture of fruit stones and resin matrix is introduced into the mold and allowed to dry, precipitating the matrix at the base of the plate to cover the natural tissue and improve the mechanical characteristics. Once dry, proceed to unmold and store the product obtained.

It should be noted that the fruit stones are not subjected to a prior crushing step, but are applied whole to the panel according to the present invention. In this way, the surface of the panel has cavities typical of the union of the different bones that gives the set its own characteristics that influence the acoustic absorption results. Indeed, after conducting various experiments, the present inventors have quite surprisingly and unexpectedly discovered that uncrushed fruit pits provide a better acoustic conditioning characteristic, especially at low frequencies, as compared to crushed fruit pits. In addition, not crushing the fruit stones also provides an advantage in terms of energy expenditure and, therefore, the cost of the process according to the present invention.

By means of the previously described manufacturing process, a construction panel according to the present invention is obtained. For example, the building panel can have a width of 600, 900 or 1200 mm, a length of 600, 1000 or 2000 mm and a thickness of 2 to 5 cm.

It should also be mentioned that, as will be seen below, the combination of a natural fiber base with a mixture of fruit pits and resin provides an unexpected synergistic effect in terms of the acoustic properties of the panel obtained. In effect, a panel according to the present invention has an acoustic absorption coefficient greater than the sum of the acoustic absorption coefficients of similar panels composed solely of natural fibers and solely of fruit pits, especially at low frequencies.

Construction panel according to the present invention presents the highest acoustic absorption coefficient at frequencies between 250 and 1500 Hz, preferably between 750 and 1250 Hz.

According to the invention, the acoustic absorption coefficient at frequencies between 750 and 1250 Hz is between 0.45 and 0.62.

In the following, specific examples of manufacturing panels according to the present invention are disclosed.

examples

The construction panel manufactured in this case is composed of natural coconut fiber, ecological resin and fruit bone (cherry, olive, apricot and peach, in this case).

The thickness of the proposed panel is 25mm of coconut fiber and 25mm of mixed fruit stones, however, the thickness of the coconut fiber can be doubled and the thickness of the layer of stones increased to achieve a better absorption of the superior sound. It is the case that increasing these thicknesses also increases the value of absorbed frequencies, that is, it works better to increase absorption at low frequencies. These variations are between 10 and 15 percent.

The proportion of different types of fruit pits in the mix is equal parts by volume. That is, the mixture of bones is made with 25% by volume of each type of bone.

Bone density is calculated from the weight of each bone and the volume of water it displaces. To carry out the calculation and given the dispersion of values typical of the diversity of shapes and thicknesses of the bones, an average is made with 50 bones of each class, obtaining the following density results.

Table 1: Bone density

The matrix is water-based resin, sustainable, conceived or called binder of aggregates In the examples of the present invention, a mono-component ecological resin has been used to fix gravel. The amount of resin necessary to form the matrix of the composite is obtained from the ratio obtained for each type of bone between the weight of resin and the weight of the bone. This relationship is obtained experimentally by weighing 10 typical bones without resin, immersing them in it, and once out of the resin and drained (that is, when it no longer drips) they are weighed again so that by means of a simple subtraction the weight can be known. of fresh resin needed for each type of bone.

According to formula (1) the ratio between the weight of resin and the weight of bone R ^hr is calculated.

R ^hr = P ^mr /P ^mh (1)

Table 2: Relationship between resin and fruit stone

To determine the weight of the resin when it dries, a quantity of resin has been poured and weighed into a glass and waited for its total drying, weighing again. The water-based resin used has a dry weight of 54% of its fresh weight. From this value, the mean weight of already dry resin by type of bone (Pmrs) has been determined. Adding the average weight of a raw bone plus the dry resin, the weight of the bone with dry resin (Pmhrs) has been obtained.

Table 3 calculates the weight of bones of each type to obtain 851.90 kg of mixture 25% volume of each type of bone. These quantities are calculated by multiplying the density of each bone by the amount by one or proportion of bone to be incorporated. As a numerical example, a volume corresponding to a plate of 0.6m x 0.6m x 0.025m = 0.009 m3 is filled with this mixture. To calculate the necessary kg of mixture to be used to fill this volume, several calculations have to be made. First, a parameter called apparent density must be defined. This parameter is obtained from the specimens or test tubes made with the mixture of bones in equal parts with resin, which are used to measure acoustic absorption with an impedance or Kundt tube of 100 mm diameter. Several cylindrical specimens of various thicknesses and 100 mm in diameter are used. Dividing their weight by the volume of the cylinder they fill, an average value of 600.53 kg/m3 is obtained, which must be considered as the apparent density with set resin of that mixture in equal parts (In the case of other proportions of bones, bulk density may vary due to a granulometric effect).

From the value of the apparent density, the weight of the plate with a volume of 0.009 m3 is obtained:

Weight of the plate of bones amalgamated with the set resin (without the coconut fiber) = = 600.53 kg/m3 x 0.009 m3 = 5.4 kg.

The weight of the dry resin that it incorporates must be subtracted from this weight in order to establish the weight ratio for each type of bone.

This quantity of resin has been measured from the manufacture of the specimens or test tubes, resulting in approximately 0.4 kg of dry resin.

In this way, it can be established that the weight of the final plate without resin (Ppf) is 5 kg.

From these data, the weight of the fruit bone of the board and the resin can be obtained according to the following table 3.

Table 3. Weight of fruit bone and weight of fresh board resin.

The following describes how the values in the previous table are obtained:

The density of the fruit bone is obtained from table 1.

The fruit stone weight is obtained by multiplying the density by the volume percentage of the fruit stone:

Fruit stone weight in 1 m3 = fruit stone density x proportion of each stone.

Fruit stone weight ( P sat) is obtained using the following formula (2):

P sat = P pf x d h x ph / d ht (2)

P sat - weight of fruit stones on board,

P pf - final plate weight without resin,

d h - fruit stone density, which is calculated according to table 1 of the report,

ph - the proportion of each bone is taken, for example, 0.25,

d ht - average density of all bones from table 3. In this example 851.90.

Fruit stone weights can be obtained in panels of different proportions, showing the example of a panel with 25% volume of each fruit stone.

The relationship between the weight of the resin and the weight of the bone is obtained from Table 2.

To obtain the value of fresh resin weight ( P mr) required for each fruit bone, the following formula (3) is used:

P mr = R hr XP sat (3)

P mr - fresh resin weight of each bone on board,

R hr - ratio between the weight of resin and the weight of the bone, which is calculated according to table 2, P sat - weight of bones in board calculated according to the above formula.

The weight of dry resin on the board is obtained by multiplying the fresh resin by 0.54, which is the percentage of dry resin weight with respect to fresh resin.

Using the formulas described above, Table 3 shows the weight of each type of fruit stone from the example board and the fresh resin needed to incorporate to optimize its manufacture, with a total of 742.73 grams of resin needed to make the board.

The manufacturing procedure for this board or panel consists, firstly, in placing a layer of natural fibers, such as coconut fiber, with a thickness of about 25 mm, with an apparent density of 61.15 kg/m3, in a mold of the dimensions of the panel to be manufactured. The next stage is to mix the fruit pits in a container. For example, according to the present example, a mixture of cherry, olive, apricot and peach stones is used with a proportion of 25% by volume of each of them, with the ecological resin matrix. The mixing stage is continued until a compact, united and firm mass is achieved.

Next, the mixture of bones with the mixed resin is introduced into the mold until it completely impregnates each bone, applying a pressure of 20 N/m2 to even out the surface and generate a bond between the natural coconut fiber and the bones. It is convenient to carry out this stage at room temperature, specifically at not less than 15°C, so as not to delay the drying of the resin. Preferably, the humidity is about 70%, with the matrix precipitating to the bottom of the plate to coat the plate. layer of natural fibers. Once dry, after approximately 24 hours, proceed to unmold and store the product obtained.

Although a specific example has been described in which a combination of four types of bones is used in equal proportions (each at 25% by volume), it is also possible to make building panels according to the present invention with combinations of bones of fruits in other proportions. To do this, it will be necessary to recalculate the amount of resin needed as described above. Acoustic coefficient results may vary within a range of plus or minus 15 percent in the frequency range of maximum sound absorption. For example, apart from the equal volume combination of bones, other combinations could be made with proportions of 10, 20, 30 and 40 percent by varying the percentage assignment to each type of bone. The following table 4 shows some examples of these possible mixtures:

Table 4. Percentages mixing different panels.

Sound absorption tests were performed with building panels according to various embodiments of the present invention. As will be seen below, it has been found that incorporating a natural fiber base layer to the fruit bone panel considerably improves acoustic conditioning, with absorption at maximum frequencies between 750 and 1250 Hz. This frequency absorption peak occurs at lower frequencies than those usually obtained. Indeed, normally the difficulty in sound absorption occurs more at low frequencies, so the bilayer panel (layer of uncrushed fruit stones and resin layer of natural fiber) proposed by the present invention has an added interest with respect to to the currently known panels.

The following table 5 presents various properties of the components used in the manufacture of the construction panel separately, just to understand that the size and shape of the bones influence the granulometry of the assembly. In the case of composing a panel with different proportions, it would be necessary to redo the corresponding calculations:

Table 5. Construction panel component properties.

The measuring instrument used in this test was an acoustic impedance tube or Kundt tube, in this case with an internal diameter of 100 mm, and it allows determining the acoustic absorption coefficient in the range between 214 and 1716 Hz.

The natural fiber mentioned in figures 1 to 5 is, in all cases, coconut fiber. As can be seen in the figures, the maximum absorption value in each case is close to 1000 Hz, with the highest absorption values being obtained between 750 and 1250 Hz. In most of the panels tested, the absorption coefficient acoustics close to 0.7.

In addition, it can also be seen in the attached figures that the sum of the acoustic absorption coefficients of the two materials separately (fruit stones and natural fiber) does not correspond to the result obtained from the two materials joined in the form of a panel, therefore that the synergistic result obtained is surprising and unexpected.

Therefore, the main advantage of the present invention is to provide a natural, environmentally friendly and unique product that has the ability to act as a substitute for precast plaster and plaster panels, both vertical and vertical. horizontal, being composed of nuts bones, resin matrix and natural fibers. All this forms a material with very good thermal and acoustic qualities.

Although various preferred embodiments of the present invention have been described, it will be apparent that the person skilled in the art can apply various modifications and variations to the teachings provided herein without departing from the scope of protection defined by the claims. For example, the present invention also includes the use of other fruit pits and natural fibers, in various combinations and proportions, to make building panels of various dimensions, all of which are included within the scope defined by the appended claims.

Claims (7)

1. Construction panel of fruit pits as acoustic conditioning facing for walls and ceilings, comprising uncrushed whole fruit pits, a resin matrix and a natural fiber base. Building panel according to claim 1, characterized in that the whole fruit pits are selected from the group consisting of olive pits, cherry pits, peach pits, plum pits, apricot pits and combinations thereof. Building panel according to any of the preceding claims, characterized in that the natural fiber base is composed of a fiber selected from the group consisting of jute fibers, coconut fibers, esparto grass fibers, and combinations thereof. 4. Building panel according to claim 3, characterized in that the natural fiber is coconut fiber. 5. Construction panel according to any of the preceding claims, characterized in that the acoustic absorption coefficient at frequencies between 750 and 1250 Hz is between 0.45 and 0.62. 6. Process for manufacturing a construction panel of fruit bones according to any of claims 1 to 5, comprising the steps of: a) arranging natural fibers at the base of a mold; b) mixing uncrushed whole fruit stones with a resin matrix; c) pouring and vibrating the mixture obtained in stage b) over the natural fibers at the base of the mold; d) leaving the mixture of stage b) to dry on the basis of natural fibers; and e) demoulding a construction panel comprising uncrushed whole fruit pits, a resin matrix and a natural fiber base. Method according to claim 6, characterized in that it comprises an additional step of smoothing the bone surface by applying a small pressure after step c) and before step d).