ES3032583A1 - Production process for chipboard panels and blocks, panels and blocks obtained by said process - Google Patents

Abstract

Method for producing chipboard panels and blocks, panels and blocks obtained by said method. The present invention relates to a method for producing chipboard panels and blocks, characterized by using Ailanthus altissima remains as raw material, comprising the steps of: a) drying Ailanthus altissima remains until a moisture content of between 5% and 10% is obtained; b) crushing and sieving the product obtained in step a); c) mixing the product obtained in step b) with an adhesive material; and d) pressing to obtain panels or blocks of the desired dimensions. The present invention also relates to a panel and a block of chipboard obtained by said method. (Machine-translation by Google Translate, not legally binding)

Description

DESCRIPTION

Production process for chipboard panels and blocks, panels and blocks obtained by said process

FIELD OF INVENTION

The present invention relates to the field of construction, and more specifically to the production of chipboard panels and blocks with acoustic and thermal insulation properties used in construction.

BACKGROUND OF THE INVENTION

Wood composite panels are traditionally made from wood chips, fibers, strands, or veneers, which are treated with adhesives and hot-pressed to form laminated products. The production of these panels poses a clear environmental problem associated with the use of wood as a raw material. Indeed, if left unchecked, excessive felling of trees for timber as a raw material poses serious environmental problems associated with climate change, increased greenhouse gas emissions, soil erosion, ecosystem disruption, and more.

To try to alleviate this problem, various techniques are known related to the recovery of wood chips from particle boards, recycling of wood-derived products, and mechanical and chemical treatment procedures to obtain recycled particles. However, these procedures present limitations in terms of quality, cost, and the need for special equipment. The widespread manufacture of panels on hot plates represents an increase in energy consumption compared to the present invention and increases the complexity of the machinery used.

Sandberg's DE-AS 1201045 patent explains how to recover wood chips from pressed boards. The process is very expensive because it requires a 0.5-4 hour pressurized steam treatment that breaks down the binder resin. Furthermore, this treatment does not completely separate the chips, necessitating subsequent mechanical treatment. The recovered chips change color due to the steam treatment, diminishing their quality for subsequent uses.

Moeller's patent DE 4201201 specifies a method for mechanically recovering wood chips from wood waste and wood-derived products. In this case, the resin is not separated, resulting in chips that emit formaldehyde.

The same applies to other well-known patents (e.g., DE 4224629, WO 9824605, DE 19819988, etc.) that use wood or panel recycling. This recycling process is very costly due to many factors, such as the removal of metal waste, the need to use temperatures between 120 and 180 degrees Celsius to dissociate binders or resins, the use of steam, the need to adjust the pH of the raw material or the resulting paste, the appearance of acids, metal hydroxides, salts, oxides, amines, urea, etc., the eventual presence of formaldehyde, and the consequent deterioration of the final raw material due to these processes.

Patent PCT/ES2008/000124 uses crushed common sugarcane waste to manufacture boards using urea-formaldehyde resin which, although it is mechanically crushed without the need for heat or steam, has the disadvantage of using a toxic resin and high pressure and temperatures to manufacture the boards.

On the other hand, the scientific literature has extensively studied the sound absorption and insulation performance of various wood and agri-food industry waste products, including fruit pits, hemp fibers, kenaf fibers, esparto grass fibers, etc. However, all of them always have some drawbacks, such as fire resistance, the use of toxic synthetic resins, the non-biodegradability of all components, or other aspects already highlighted in other patents mentioned.

Therefore, there is still a need in the art for an alternative method for obtaining chipboard panels and blocks that makes it possible to eliminate or at least reduce their environmental impact, while at least maintaining or even improving the properties of the panels and blocks obtained, for example in terms of acoustic insulation, thermal insulation, mechanical properties, etc.

SUMMARY OF THE INVENTION

In order to solve the above-mentioned problems of the prior art, the present document discloses, according to a first aspect, a method for producing chipboard panels and blocks, characterized by using Ailanthus altissima remains as raw material. The method disclosed in the present invention comprises the steps of:

a) drying Ailanthus altissima remains until a moisture content of between 5% and 10% is obtained;

b) crush and sieve the product obtained in step a);

c) mixing the product obtained in step b) with an adhesive material; and

d) press to obtain panels or blocks of the desired dimensions.

Therefore, the proposed procedure seeks to use Ailanthus altissima remains in a simple and efficient manner as an alternative to conventional wood sources, thereby mitigating the problems associated with raw material availability. Indeed, Ailanthus altissima is an invasive and environmentally harmful species, so its use as a raw material in the production of building panels and blocks not only does not pose an environmental problem, but actually contributes to environmental restoration.

Furthermore, the ease of production can be exported to small producers, allowing them to quickly and efficiently obtain a quality product from previously unused waste.

The raw material chosen in this novel way offers several advantages not previously exploited in the art. On the one hand, it does not require post-treatment, as it naturally exhibits antibacterial and fungicidal properties. This is a very important aspect, as it allows for a reduction in the use of other products in the treatment of the raw material, thereby reducing process costs and increasing production speed.

Furthermore, Ailanthus altissima is very easy to press, allowing pressing at room temperature (approximately 20°C) and low pressure. Another advantage offered by the process proposed in the present invention over methods known in the art is its easy and rapid drying, further reducing associated process costs and speeding up production.

Furthermore, according to a preferred embodiment of the present invention, the process comprises using a fast-drying single-component polyurethane as the adhesive material in step c). This again allows subsequent pressing at room temperature, with an approach that is easy to reproduce and easy to extrapolate to small-scale industries.

Another feature of a further preferred embodiment of the method according to the present invention consists of immersing the resulting panel or block in a fluid paste composed of a mixture of water, cement, and/or lime. This increases the strength, durability, and fire resistance of the resulting panel or block.

According to a further aspect, the present invention also relates to a panel and a block obtained by the method according to the first aspect of the present invention.

As used herein, the term “panel” refers to a board of lesser thickness (as compared to a “block” as defined herein below), for example with a thickness of 2 cm. Panels may have dimensions of, for example, 60x60x2 cm for false ceiling panels or 240x60x2 cm for roof panels. On the other hand, the term “block” as used herein refers to a board of greater thickness (as compared to a “panel” as defined above), for example with a thickness of 20 cm, such as a wall block with dimensions of 20x60x20 cm for structural use.

Throughout the description and claims, the word "comprises" and its variations are not intended to exclude other technical features or components. In addition, the word "comprises" includes the case "consists of". For those skilled in the art, other objects, advantages and features of the invention will be apparent in part from the description and in part from the practice of the invention. The following examples are provided by way of illustration, and are not intended to be limiting of the present invention. In addition, the present invention covers all possible combinations of embodiments indicated herein.

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, provided by way of example, and which should not be construed as limiting the invention in any way.

Figure 1 shows a graph of the sound absorption coefficient of panels of different densities according to embodiments of the present invention for frequencies between 200 and 1700 Hz.

Figure 2 shows a graph of the absorption coefficient of different thicknesses of the PP5 panel according to a preferred embodiment of the present invention.

Figure 3 shows a graph of the acoustic insulation in dB of 6 samples with different apparent densities according to preferred embodiments of the present invention.

Figure 4 shows a graph of the mechanical behavior of 6 samples with different apparent densities according to preferred embodiments of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMPLOYMENTS

According to a preferred embodiment, the invention provides a method for producing particle board panels and blocks using Ailanthus altissima remains as raw material. The method according to the preferred embodiment of the present invention comprises the steps of:

a) dry Ailanthus altissima remains, preferably outdoors for 30 days, until a moisture content of between 5% and 10% is obtained;

a’) optionally stripping and cutting the ends of the dried product obtained in step a);

b) crushing and sieving the product obtained in step a') to remove unwanted particles, such as earth or small stones. After sieving, preferably crushed chips with a size between 3.15 mm and 16 mm are selected;

c) mixing the product obtained in step b) with an adhesive material, preferably selected from the group consisting of single-component polyurethane, urea-formaldehyde and lignin, more preferably single-component polyurethane; and

d) pressing to obtain panels or blocks of the desired dimensions, more preferably pressing at a temperature of approximately 20 °C.

The pressure used in step d) will depend on the desired density of the final panel or block. For low-density panels, a displacement is applied until the desired thickness is obtained. For panels and blocks with a high density, 600-1200 kg/m3, step d) is carried out at a pressure of 500-1000 kPa.

Stage d) is carried out in a mould that can have different shapes to improve acoustic behaviour.

According to a further preferred embodiment of the present invention, the method further comprises the step:

e) immersing the product obtained in step d) in a fluid paste, the fluid paste being composed of a mixture of water with a component selected from the group consisting of cement, lime or both, more preferably the fluid paste comprises between 30% and 70% water and the remainder of the selected component of cement and/or lime.

Thanks to this additional final stage, the fire protection, strength, and durability of the resulting panels and blocks are improved. Furthermore, the lime helps retain atmospheric CO2.

As mentioned above, the present invention also relates to chipboard panels and blocks for construction obtained by the method according to any of the embodiments of the present invention.

Thanks to the process disclosed by the present invention, a biodegradable, fire-resistant, highly mechanically resistant and, ultimately, functional product is obtained, suitable for being considered a sound-absorbing acoustic panel.

The present invention advantageously provides the use of Ailanthus altissima as a raw material, thereby mitigating the need to fell conventional and native trees. Furthermore, this raw material requires less drying, thereby saving energy and related costs compared to other known products on the market. As mentioned above, this raw material also exhibits antibacterial and fungicidal properties, as well as good durability. It also exhibits increased resistance to moisture and a thickness recovery capacity after immersion in water. Finally, by utilizing Ailanthus altissima as a raw material, which is an invasive species that represents an abundant and generally unused resource, the method of the invention allows for a reduction in environmental impact.

Furthermore, the process of the present invention can be carried out using conventional machinery in the particle board industry, allowing easy reproduction of the process.

As will be seen in the following examples, the panels and blocks according to the present invention provide excellent noise and thermal insulation performance, as well as good mechanical resistance. Furthermore, the final finish with lime or fluid cement provides greater fire resistance, durability, and mechanical strength.

Below are presented by way of illustration several examples of manufacturing panels and blocks according to the present invention, as well as mechanical tests to which they were subjected to determine their properties of acoustic insulation, thermal insulation, mechanical resistance, etc.

EXAMPLES

Panels were manufactured from crushed ailanthus, agglomerated with different types of adhesives, resins, or ceramic binders, depending on the use or application. Different types of panels were produced with different apparent densities. The same amount of crushed material was used, compressing the sample to thicknesses of 10, 20, 30, 40, 50, and 60 mm using pressures appropriate for each thickness. The test samples were cylindrical, 100 mm in diameter.

For each apparent density, the sound absorption curve varies, so one or the other can be used depending on the application or the characteristics of the room to be conditioned. Table 1 shows the samples manufactured with the same weight of crushed material for different thicknesses.

Table 1. Thickness, apparent density and thermal conductivity of the manufactured samples

As can be seen in the attached figures, as the panel density increases, the sound absorption coefficient decreases (see Figures 1 and 2) and insulation increases (see Figure 3), except for the lowest-density panel (PP6), where absorption decreases compared to panel PP5 because it no longer has sufficient density (see Figure 1).

Therefore, the best absorbent performance was found in sample PP5, with a bulk density of 277.94 kg/m3. Sample PP5 was therefore used to make samples with thicknesses of 10, 20, 30, 40, 50, and 60 mm for further testing.

Taking advantage of the fact that, as can be seen in Figure 2, the range of absorbed frequencies varies for each thickness, a further feature of the present invention can be added: the use of panels of different thicknesses to cover the surface of a room, thereby absorbing sound from a wider frequency range. A surprising effect that can be highlighted from this graph is that a panel made of different thicknesses with the same density allows absorption in a frequency range between 250 and 1500 Hz, a range that coincides with the low frequencies that are generally difficult to absorb. The 4 cm thick PP5 material has a prominent absorption peak at 500 Hz, which represents another surprising and unexpected effect.

With regard to acoustic insulation, the samples with different apparent densities indicated above were tested, obtaining the results shown in Figure 3. As mentioned above, in this case the opposite effect is observed, that is, the higher the apparent density, the greater the insulation, concluding that a multi-layer panel with PP1 PP5 will have good absorption and insulation properties.

Regarding mechanical behavior, 250x50 mm test specimens of varying thicknesses were prepared as samples. The results of the mechanical testing are shown in Figure 4. It is noteworthy that the PP1 specimens performed best, with higher densities, while lower densities reduced the force that could be resisted.

Below is a comparison with another product for similar applications. Although there are not many acoustic panels made from wild waste currently on the market, the closest match is wood chip agglomerates with magnesite (Termochip panel, TKH-15-40-19). The sound absorption of these panels is indicated in the table below, obtained from European Technical Assessment ETA 08/0295 of January 19, 2016.

The following table presents a comparison of the properties of the Termochip panel with a panel according to a preferred embodiment of the present invention:

As can be seen, the panel according to the present invention exhibits significantly greater sound absorption compared to the prior art Termochip panel. Furthermore, as mentioned above, the present invention provides improved environmental protection and increased utilization of waste materials. Furthermore, it successfully controls the spread of an invasive species whose negative impact can be classified into three categories:

- damage to native species by absorbing soil resources;

- damage to ecosystems by changing the natural composition of the ecosystem by reducing biodiversity;

- socioeconomic damage, since the roots penetrate rock crevices and break them, cracking streets and roads, lifting sidewalks, and even knocking down walls. Furthermore, they can negatively affect agricultural soils due to the impact of the negative allelopathic substances in the leaves. The toxicity of the leaves can also affect livestock and honey production.

Although the invention has been described with reference to a preferred embodiment thereof, the person skilled in the art will understand that modifications and variations may be applied to said embodiment without thereby departing from the scope of protection defined by the appended claims.

Claims (12)

1. Production process for chipboard panels and blocks, characterized by using Ailanthus altissima remains as raw material, comprising the following stages: a) drying Ailanthus altissima remains until a moisture content of between 5% and 10% is obtained; b) crush and sieve the product obtained in step a); c) mixing the product obtained in step b) with an adhesive material; and d) press to obtain panels or blocks of the desired dimensions. 2. Method according to the preceding claim, characterized in that step a) comprises drying Ailanthus altissima remains in the open air for 30 days. 3. Method according to any of the preceding claims, characterized in that it further comprises a step a'), following step a), which consists of stripping and cutting the ends of the dried product obtained in step a). 4. Method according to any of the preceding claims, characterized in that step b) comprises selecting, after crushing and sieving, chips whose size is between 3.15 mm and 16 mm. 5. Method according to any of the preceding claims, characterized in that the adhesive material used in step c) is selected from the group consisting of single-component polyurethane, urea-formaldehyde and lignin. 6. Method according to any of the preceding claims, characterized in that the pressing in step d) is carried out at room temperature. 7. Method according to claim 6, characterized in that the pressing is carried out at a temperature of 20 °C. 8. Method according to any of the preceding claims, characterized in that the pressing in step d) is carried out at a pressure of 500-1000 kpa, to obtain panels and blocks with a density of 600-1200 kg/m3. 9. Method according to any of the preceding claims, characterized in that it further comprises a step e) of immersing the product obtained in step d) in a fluid paste, the fluid paste being composed of a mixture of water with a component selected from the group consisting of cement, lime or both. 10. Method according to claim 9, characterized in that the fluid paste comprises between 30% and 70% water. 11. Chipboard panel obtained by a method according to any of claims 1 to 10. 12. Block of agglomerates obtained by a method according to any of claims 1 to 10.