CN112092117A - A kind of preparation method of cross-mesh oriented lightweight board - Google Patents

Abstract

The invention discloses a method for preparing a cross-grid oriented lightweight board. The steps are (1) longitudinal sectioning: cutting eucalyptus veneer into veneer strips; (2) gluing: weighing the adhesive and the veneer strips, Modified adhesive, smear the modified adhesive on the veneer; (3) Paving: use the whole eucalyptus veneer as the lower layer, and arrange the double-sided glued veneer in parallel and equidistant from left to right on the lower layer. As the first layer, the double-sided glued veneer strips are arranged in parallel and equidistant from the front to the back on the first layer. The total layer of veneer strips is used as the middle layer, and finally the whole eucalyptus veneer is placed on the middle layer as the upper layer to obtain a slab; (4) hot pressing to obtain a cross-grid oriented lightweight board. The invention can obtain a board with better density and mechanical properties and meet the requirements of lightweight boards by adjusting the size of the gaps in the cross-arrangement of the veneer strips, the number of layers of the veneer strips, the hot pressing parameters and the thickness of the board.

Description

A kind of preparation method of cross-mesh oriented lightweight board

technical field

The invention relates to a preparation method of a lightweight board, in particular to a preparation method of a cross-grid oriented lightweight board.

Background technique

Lightweight board, as the name suggests, is a board that is lighter in quality than ordinary boards and whose strength meets the standard for use. Lightweight wood-based panels save raw materials in manufacturing, the cost is relatively reduced, and the price of use will also be reduced, which makes light-based wood-based panels a trend. Reducing the quality of the board can bring a lot of convenience to the transportation and assembly of consumers and wholesalers, and reduce transportation costs, which is the point of view of the proponents. However, although lightweight wood-based panels have the above advantages, wood-based panel manufacturers are reluctant to change the original production process in their factories. Moreover, because it is a new type of wood-based panel, the market's recognition of it is also very low, and furniture retailers will not pay extra for a new product, so it is difficult to implement lightweight wood-based panels.

In recent years, many countries and regions have been faced with the difficult situation of shortage of wood resources, and the increase in material costs has greatly increased, and this phenomenon will not be improved in a short period of time. reduced. Many enterprises and institutions have comprehensively considered the issues of resources and costs, and have begun to study lightweight wood-based panels. The research and development of lightweight wood-based panels has gradually become a hot issue. The quality is reduced, and the research on the structural design of lightweight boards is still very lacking. The development of new lightweight boards can not only effectively utilize wood resources, but also meet the requirements of different industries for boards. Therefore, there is an urgent need for a new type of wood-based panel preparation process that can improve the performance of oriented lightweight panels, and to prepare a new type of wood-based panel that is lighter in weight than conventional panels and meets the requirements in strength, in order to optimize its physical and mechanical properties.

The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person of ordinary skill in the art.

SUMMARY OF THE INVENTION

In view of the above technical problems, the present invention invents a method for preparing a cross-grid oriented lightweight board, aiming to obtain a preparation method with a simple preparation process, low cost, and good mechanical properties of the obtained oriented lightweight board.

For achieving the above object, the technical scheme provided by the invention is as follows:

A preparation method of a cross-mesh oriented light-weight board, comprising the following operation steps:

(1) Longitudinal section: cut the eucalyptus veneer into veneer strips, the size of the veneer strip is 40cm-120cm in length, 1.0cm-3.0cm in width, and 0.8cm-2.5mm in thickness;

(2) gluing: weigh the adhesive and the veneer strip obtained in step (1) according to a certain amount, modify the adhesive, and evenly apply the modified adhesive on both sides of the veneer strip;

(3) Paving: use the whole eucalyptus veneer as the lower layer, and arrange the double-sided glued veneer strips in step (2) on the lower layer in parallel and equidistant from left to right, as the first layer, and then on the first layer. The double-sided glued veneer strips are arranged in parallel and equidistant from front to back. As layer II, layer I and layer II form a cross grid structure, and continue to arrange the veneer strips in a mutually perpendicular manner. The equidistant distance is 1-5cm, a total of 9-15 layers (including layer I and layer II) are arranged, and the total layer of veneer strips arranged perpendicular to each other is used as the middle layer, and finally the whole eucalyptus veneer is placed on the middle layer as the upper layer. Slab, the thickness of the obtained slab is 10mm-15mm;

(4) Hot pressing: hot pressing the slab obtained in step (3), the holding time is 10-20min, the pressure is 1.0-2.0Mpa, and the hot-pressing temperature is 120-150°C, that is, the cross-grid oriented light weight is obtained. plate;

Wherein, when the width of the veneer strip in step (1) is 2cm, the distance between the steps (3) is 4cm, a total of 12 layers are arranged, and the thickness of the obtained slab is 10mm;

When the width of the veneer strip in step (1) is 1cm, the distance in step (3) is 2cm, 9 layers are arranged in total, and the thickness of the obtained slab is 10mm;

When the width of the veneer strips in step (1) is 3cm, the distance between them in step (3) is 3cm, a total of 15 layers are arranged, and the thickness of the obtained slab is 12mm;

Wherein, when the width of the veneer strip in step (1) is 2cm, the distance between the steps (3) is 4cm, a total of 9 layers are arranged, and the thickness of the obtained slab is 12mm;

When the width of the veneer strips in step (1) is 2cm, the distance between them in step (3) is 3cm, a total of 15 layers are arranged, and the thickness of the obtained slab is 10mm;

When the width of the veneer strip in step (1) is 3cm, the distance in step (3) is 4cm, 12 layers are arranged in total, and the thickness of the obtained slab is 10mm;

When the width of the veneer strip in step (1) is 3 cm, the distance between them in step (3) is 2 cm, 15 layers are arranged in total, and the thickness of the obtained slab is 12 mm.

Preferably, the width of the veneer strip described in step (1) is 2.0 cm.

Preferably, in the step (2), the adhesive and the veneer are taken according to the mass ratio of the adhesive to the veneer obtained in the step (1) of 0.15:1.

Preferably, in step (2), a flour modified adhesive is added, the flour is high-gluten flour, the amount of addition is 25% of the quality of the adhesive, and the amount of sizing is that the modified adhesive is used in an amount of 70% of the quality of the veneer. 15%; the adhesive is urea-formaldehyde adhesive.

Preferably, the pressure holding time described in step (4) is 15min, the pressure is 1.5Mpa, and the hot-pressing temperature is 125°C.

Compared with the prior art, the present invention has the following beneficial effects:

According to the method of the invention, the eucalyptus veneer is cut into veneer strips with a fixed width, double-sided gluing is carried out, and the middle layer of the board is cross-arranged, and the upper and lower layers are composited with eucalyptus veneer. Light-weight plate, cross-grid oriented lightweight plate is obtained; the present invention can obtain better density and mechanical properties and meet the requirements of light-weight by adjusting the size of the voids in the cross-arrangement of the single-slats, the number of layers of the single-slats, the hot-pressing parameters and the thickness of the plate. The board required by the board shows a strong application prospect.

Description of drawings

Fig. 1 is the process schematic diagram of the method of the present invention.

Figure 2 is a slab test piece obtained by the method of the present invention.

Figure 3 is the effect of different factors on the density of the cross-mesh oriented lightweight board prepared by the method of the present invention.

Fig. 4 is the influence of different factors on the elastic modulus of the cross-mesh oriented lightweight board prepared by the method of the present invention.

Figure 5 shows the influence of different factors on the static bending strength of the cross-mesh oriented lightweight board prepared by the method of the present invention.

Fig. 6 is the influence of different factors on the bonding strength of the cross-mesh oriented lightweight board prepared by the method of the present invention.

Fig. 7 is the influence of different factors on the water swelling ratio of the cross-mesh oriented lightweight board prepared by the method of the present invention.

Detailed ways

The following will describe in detail the specific embodiments in conjunction with the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments. The raw materials used in the examples and the actual ones are commercially available unless otherwise specified.

Example 1

A preparation method of a cross-grid oriented lightweight board, the operation steps are as follows:

(1) Longitudinal section: The eucalyptus veneer is cut into veneer strips with a precision table saw, and the size of the veneer strip is 42cm in length, 1.0cm in width, and 1mm in thickness;

(2) gluing: weigh the veneer and the urea-formaldehyde adhesive in a mass ratio of 1:0.15 according to the veneer strip obtained in step (1) and the urea-formaldehyde adhesive, add the high-gluten flour-modified urea-formaldehyde adhesive with a mass of 25% of the urea-formaldehyde adhesive, and add the urea-formaldehyde adhesive. The modified urea-formaldehyde adhesive is poured into the manual gluing machine, and the veneer strips obtained in step (1) are neatly spread on the tray in batches, and the veneer strips are gently rolled on the paved veneer strips with the gluing machine. Make the adhesive on both sides of the veneer strip evenly coated, and the amount of sizing is 15% of the mass of the veneer strip after modification;

(3) Pavement: use the whole eucalyptus veneer as the lower layer, and arrange the double-sided glued veneer strips from left to right on the lower layer in parallel and equidistant in step (2). layer, and then arrange the double-sided glued veneer strips in parallel and equidistant from the front to the back on the I layer, and the spacing between the veneer strips is 2cm. The veneers are arranged vertically, with a total of 9 layers (including layers I and II). A slab is obtained, the thickness of the obtained slab is 10mm, and the size of the upper layer and the lower layer is 42cm×42cm;

(4) Hot pressing: put the slab obtained in step (3) into the experimental hot press for hot pressing to obtain a slab of 10 mm, the holding time is 15 min, the pressure is 1.5 Mpa, and the hot pressing temperature is 125 ° C, That is, the cross-mesh oriented lightweight board is obtained.

Slab storage: After the hot pressing in step (4), the obtained slabs are taken out and stored for 5 days until testing.

Example 2

A preparation method of a cross-mesh oriented light-weight board, comprising the following operation steps:

(1) Longitudinal section: The eucalyptus veneer is cut into veneer strips with a precision push table saw, and the size of the veneer strip is 40cm in length, 3.0cm in width, and 0.8mm in thickness;

(2) gluing: weigh the veneer and the urea-formaldehyde adhesive in a mass ratio of 1:0.15 according to the veneer strip obtained in step (1) and the urea-formaldehyde adhesive, add the high-gluten flour-modified urea-formaldehyde adhesive with a mass of 25% of the urea-formaldehyde adhesive, and add the urea-formaldehyde adhesive. The modified urea-formaldehyde adhesive is poured into the manual gluing machine, and the veneer strips obtained in step (1) are neatly spread on the tray in batches, and the veneer strips are gently rolled on the paved veneer strips with the gluing machine. Make the urea-formaldehyde adhesive on both sides of the veneer strip evenly coated, and the amount of urea-formaldehyde adhesive used after modification is 15% of the mass of the veneer strip;

(3) Pavement: use the entire eucalyptus veneer as the lower layer, and arrange the double-sided glued veneer strips in step (2) on the lower layer in parallel and equidistant from left to right, and the distance between the veneer strips is 3cm, as I layer, and then arrange the double-sided glued veneer strips in parallel and equidistant from the front to the back on the first layer. The distance between the veneer strips is 3cm. The veneers are arranged vertically, with a total of 15 layers (including layers I and II). A slab is obtained, the thickness of the obtained slab is 12mm, and the size of the upper layer and the lower layer is 42cm×42cm;

(4) Hot pressing: put the slab obtained in step (3) into the experimental hot press for hot pressing to obtain a slab of 12 mm, the holding time is 10 min, the pressure is 1.0 Mpa, and the hot pressing temperature is 150 ° C, That is, the cross-mesh oriented lightweight board is obtained.

Slab storage: After the hot pressing in step (4), the obtained slabs are taken out and stored for 3 days until testing.

Example 3

A preparation method of a cross-grid oriented lightweight board, the specific operation steps are as follows:

(1) Longitudinal section: The eucalyptus veneer is cut into veneer strips with a precision table saw, and the size of the veneer strip is 120cm in length, 2.0cm in width, and 2.5mm in thickness;

(2) gluing: weigh the veneer and the urea-formaldehyde adhesive in a mass ratio of 1:0.15 according to the veneer strip obtained in step (1) and the urea-formaldehyde adhesive, add the high-gluten flour-modified urea-formaldehyde adhesive with a mass of 25% of the urea-formaldehyde adhesive, and add the urea-formaldehyde adhesive. The modified urea-formaldehyde adhesive is poured into the manual gluing machine, and the veneer strips obtained in step (1) are neatly spread on the tray in batches, and the veneer strips are gently rolled on the paved veneer strips with the gluing machine. Make the urea-formaldehyde adhesive on the veneer evenly coated, and the sizing amount is 15% of the mass of the veneer after modification;

(3) Pavement: use the whole eucalyptus veneer as the lower layer, and arrange the double-sided glued veneer strips in step (2) on the lower layer in parallel and equidistant from left to right, and the distance between the veneer strips is 4cm, as I layer, and then arrange the double-sided glued veneer strips in parallel and equidistant from the front to the back on the I layer. The distance between the veneer strips is 4cm. The veneers are arranged vertically, with a total of 12 layers (including I and II layers). A slab is obtained, the thickness of the obtained slab is 10mm, and the size of the upper layer and the lower layer is 42cm×42cm;

(4) Hot pressing: put the slab obtained in step (3) into the experimental hot press for hot pressing to obtain a slab of 10 mm, the holding time is 15 min, the pressure is 1.5 Mpa, and the hot pressing temperature is 125 ° C, That is, the cross-mesh oriented lightweight board is obtained.

Slab storage: After the hot pressing in step (4), the obtained slabs are taken out and stored for 2-5 days until testing.

Example 4

A preparation method of a cross-grid oriented lightweight board, the specific operation steps are as follows:

(1) Longitudinal section: The eucalyptus veneer is cut into veneer strips with a precision table saw, and the size of the veneer strip is 120cm in length, 2.0cm in width, and 2.5mm in thickness;

(2) gluing: weigh the veneer and the urea-formaldehyde adhesive in a mass ratio of 1:0.15 according to the veneer strip obtained in step (1) and the urea-formaldehyde adhesive, add the high-gluten flour-modified urea-formaldehyde adhesive with a mass of 25% of the urea-formaldehyde adhesive, and add the urea-formaldehyde adhesive. The modified urea-formaldehyde adhesive is poured into the manual gluing machine, and the veneer strips obtained in step (1) are neatly spread on the tray in batches, and the veneer strips are gently rolled on the paved veneer strips with the gluing machine. Make the urea-formaldehyde adhesive on the veneer evenly coated, and the sizing amount is 15% of the mass of the veneer after modification;

(3) Pavement: use the whole eucalyptus veneer as the lower layer, and arrange the double-sided glued veneer strips in step (2) on the lower layer in parallel and equidistant from left to right, and the distance between the veneer strips is 4cm, as I layer, and then arrange the double-sided glued veneer strips in parallel and equidistant from the front to the back on the I layer. The distance between the veneer strips is 4cm. The veneers are arranged vertically, with a total of 9 layers (including layers I and II). A slab is obtained, the thickness of the obtained slab is 12mm, and the size of the upper layer and the lower layer is 42cm×42cm;

(4) Hot pressing: put the slab obtained in step (3) into the experimental hot press for hot pressing to obtain a slab of 10 mm, the holding time is 15 min, the pressure is 1.5 Mpa, and the hot pressing temperature is 125 ° C, That is, the cross-mesh oriented lightweight board is obtained.

Slab storage: After the hot pressing in step (4), the obtained slabs are taken out and stored for 2-5 days until testing. Detection:

According to the preparation method of Example 1, each parameter was adjusted according to the corresponding data in Table 1, and the remaining operations were exactly the same as Example 1 to prepare an oriented lightweight board (the number 1 in Table 1 is Example 1).

Table 1

The static bending strength, elastic modulus, internal bonding strength, density, and water absorption thickness expansion ratio of the prepared oriented lightweight board were detected, and the results are shown in Table 2 (the number 1 in Table 2 is the data obtained in Example 1, Due to the large amount of data, the physical and mechanical properties of the board obtained in Example 2-4 all meet the requirements for OSB/1 type in LY/T1580-2010 "Oriented Strand Board", and the data of Example 2-4 is not included in Table 2. ), the data obtained in Table 2 is analyzed by range analysis, and Figure 3-7 is obtained:

Table 2

Figure 3 shows the density comparison of each group of cross-mesh oriented light-weight boards in the above 9 groups of experiments: Among them, the experimental numbers 1, 6, and 8 are the cross-mesh oriented lightweight boards with a thickness of 10mm; the experiment numbers are, 4 and 9 are the plates with a thickness of 12mm, and the experimental serial numbers are 3, 5, and 7, and the plates are obtained with a thickness of 15mm. It can be clearly seen from the above figure 3 that the thickness of the 15mm plate has the smallest density and the lightest weight; followed by 12mm The highest density is the plate with a thickness of 10mm. It can be preliminarily concluded that the smaller the thickness of the board, the tighter the veneer is compressed and the higher the density. On the other hand, the more layers of the veneer, the smaller the thickness of the veneer, the closer the veneer is attached, and the greater the density, the smaller the interval of the veneer, the density also changes with the change. Small.

Figure 4 shows that the elastic modulus increases with the increase of the width of the veneer strip. It first decreases and then rises within the range of the number of veneer layers. The difference between the elastic modulus of the 9-layer and 12-layer plates is not very large. The number of layers of the inner veneer indirectly affects the elastic modulus; the elastic modulus decreases with the increase of the thickness of the plate and the interval of the veneer. The reason may be that the wider the veneer, the smaller the gap left in the plate, and the elasticity The modulus also increases. The greater the thickness of the sheet, the less compact the veneer strips are, resulting in a decrease in the elastic modulus; the larger the spacing between the veneer strips, the larger the gap in the sheet, and the corresponding reduction in the elastic modulus.

Figure 5 shows that the static bending strength increases with the increase of the width of the veneer. It may be that the width of the veneer indirectly affects the size of the internal void of the plate. When the number of veneer layers increases, it first decreases from 18.57 to 28.61 , and then rises again. The static flexural strength first decreased and then increased with the increase of the veneer spacing. When the veneer spacing was 2cm, the static flexural strength reached 26.87: the static flexural strength decreased with the increase of the thickness of the plate. The reason for the analysis may be the plate The inner veneer slats are not compacted and the fit is not tight, resulting in a decrease in static bending strength. According to the standard LY/T 1580-2010 "Oriented Strand Board Standard", the mechanical properties of non-bearing boards in dry state require that the static bending strength of the 6-10mm sheet should be greater than 22, and the static bending strength of the 10-18mm sheet should be greater than 20, No. 2 The plates obtained from -5 and No. 7 did not meet the standard.

Figure 6 shows that the minimum internal bonding strength is only 0.23 when the width of the veneer strip is 3 cm, and the internal bonding strength also increases with the increase of the width in the range of 1-2 cm. The reason for the analysis may be the contact between the internal bonding strength and the material in the plate The area is related, but the width of 3cm is the lowest internal bonding strength, which may be caused by uneven sizing during the experiment; the internal bonding strength gradually decreases with the increase of the number of veneer layers. The reason may be due to The thickness of the veneer increases as the number of veneer layers increases. Due to the function of the thickness gauge, the heat of the plate is not fully transferred to the whole plate during the hot pressing process, so the internal bonding strength decreases; Within the thickness range, it first rises and then falls. The reason for the analysis may be that when the thickness of the plate is 15mm, the number of layers of some veneer barely exceeds the size of the thickness gauge, and the veneer is not fully compressed during hot pressing, resulting in the decrease of the internal bonding strength. Decrease; the internal bonding strength first decreased and then increased within the interval of veneer strips, and was the lowest when the interval was 2 cm, only 0.61MPa. The reason for the analysis may be that within the size of the specimen, when the specimen was cut, only a small part of the veneer strip contained internal, so the internal bonding strength is very small.

Figure 7 shows that the water absorption thickness expansion ratio increases with the number of veneer layers, rising steadily from 74% for 9 layers to 92%, and first increases and then decreases in terms of veneer width and veneer spacing factors , the highest values are 114% and 103% at 2cm veneer width and 3cm veneer interval. The water absorption thickness expansion rate of the plate thickness decreases from the maximum to the minimum and then increases. The LY/T 1580-2010 standard stipulates that the 24h water absorption thickness expansion rate of the board within the thickness range of 10mm ~ 18mm should be greater than 15%, and the lightweight board under all conditions meets the standard. The expansion rate of water absorption thickness is far beyond the standard. The reasons for the analysis may be uneven sizing of veneer and too many layers in the hot-pressing process. After the hot-pressing time is short, the heat is not transmitted thoroughly, resulting in no gap between the veneers. Sufficient gluing strength is fixed, so the board expands seriously and deforms seriously.

The experimental results show that the most important factors affecting the staggered lightweight board of eucalyptus veneer are the width of the veneer and the number of layers of the veneer, followed by the interval of the veneer.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise form disclosed, and obviously many changes and modifications are possible in light of the above teachings. The exemplary embodiments were chosen and described for the purpose of explaining certain principles of the invention and their practical applications, to thereby enable others skilled in the art to make and utilize various exemplary embodiments and various different aspects of the invention. Choose and change. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims (5)

1. a preparation method of a cross-mesh oriented light-weight board, is characterized in that, comprises the following operation steps: (1) Longitudinal section: cut the eucalyptus veneer into veneer strips, the size of the veneer strip is 40cm-120cm in length, 1.0cm-3.0cm in width, and 0.8cm-2.5mm in thickness; (2) gluing: weigh the adhesive and the veneer strip obtained in step (1) according to a certain amount, modify the adhesive, and apply the modified adhesive on both sides of the veneer strip; (3) Paving: use the whole eucalyptus veneer as the lower layer, and arrange the double-sided glued veneer strips in step (2) on the lower layer in parallel and equidistant from left to right, as the first layer, and then on the first layer. Arrange the double-sided glued veneer strips in parallel and equidistant from front to back. As layer II, continue to arrange the veneer strips in a mutually perpendicular manner. The equidistant distance is 1-5cm, and a total of 9-15 layers are arranged. The total layer of veneer strips arranged in a mutually perpendicular manner is used as the middle layer, and finally the whole eucalyptus veneer is placed on the middle layer as the upper layer to obtain a slab, and the thickness of the obtained slab is 10mm-15mm; (4) Hot pressing: hot pressing the slab obtained in step (3), the holding time is 10-20min, the pressure is 1.0-2.0Mpa, and the hot-pressing temperature is 120-150°C, that is, the cross-grid oriented light weight is obtained. plate; Wherein, when the width of the veneer strip in step (1) is 2cm, the distance between the steps (3) is 4cm, a total of 12 layers are arranged, and the thickness of the obtained slab is 10mm; When the width of the veneer strip in step (1) is 1cm, the distance in step (3) is 2cm, 9 layers are arranged in total, and the thickness of the obtained slab is 10mm; When the width of the veneer strips in step (1) is 3cm, the distance between them in step (3) is 3cm, a total of 15 layers are arranged, and the thickness of the obtained slab is 12mm; Wherein, when the width of the veneer strip in step (1) is 2cm, the distance between the steps (3) is 4cm, a total of 9 layers are arranged, and the thickness of the obtained slab is 12mm; When the width of the veneer strips in step (1) is 2cm, the distance between them in step (3) is 3cm, a total of 15 layers are arranged, and the thickness of the obtained slab is 10mm; When the width of the veneer strip in step (1) is 3cm, the distance in step (3) is 4cm, 12 layers are arranged in total, and the thickness of the obtained slab is 10mm; When the width of the veneer strip in step (1) is 3 cm, the distance between them in step (3) is 2 cm, 15 layers are arranged in total, and the thickness of the obtained slab is 12 mm. 2 . The preparation method according to claim 1 , wherein the width of the veneer strip described in step (1) is 2.0 cm. 3 . 3. preparation method according to claim 1 is characterized in that: in step (2), take adhesive and veneer according to the mass ratio of the adhesive and the veneer obtained in step (1) 0.15:1. 4. preparation method according to claim 1, is characterized in that: in step (2), add flour-modified adhesive, described flour is high-gluten flour, addition is 25% of adhesive quality, and sizing amount is modified The usage amount of the adhesive after curing is 15% of the mass of the veneer; the adhesive is a urea-formaldehyde adhesive. 5. The preparation method according to claim 1, characterized in that: the pressure holding time described in the step (4) is 15min, the pressure is 1.5Mpa, and the hot pressing temperature is 125°C.

Images