FI86822B - TRAEVARA AV SPAONSKIVA. - Google Patents

Abstract

Substitute lumber pieces having strengths and densities substantially equivalent to lumber are cut from single layer panels (18) of over about 1 and normally less than 4 inch thickness made from wood wafers. The wafers are oriented with their lengths having a mean deviation to the longitudinal length of the panel measured in the major plane of the panel in the range of 0 to 10 degrees and a mean deviation measured in a minimum longitudinal plane perpendicular to the major plane from 0 to about 5 degrees and have an average effective length of at least 8 inches (200 mm), and preferably an average thickness less than 0.15 inches (4 mm) and a width of at least 0.25 inches (6 mm). Lumber is made by cutting the panel longitudinally. Preferably the panels are formed to have a substantially uniform density profile throughout their thicknesses.

Description

A 86822

Lastulevvpuutavara

The present invention relates to particleboard timber: more particularly, the present invention is directed to timber articles. formed of chips oriented substantially parallel to the longitudinal axis of the timber product. and a method of making such a product.

Several patents have been granted and several articles have been published on the manufacture of wood-like products from wood particles. Similarly, it is common practice to make particle board products from wood particles. and numerous articles have been published.

In the field of oriented filamentous algae, it is common practice to make a board from particles with a maximum length of about 100 mm. and several essays and articles have been published in favor of a maximum chip length of 100 mm. However, in recently filed U.S. Patent Application No. 829,564. which is a continuation of application No. 723,641, filed April 16, 1985, has shown that great advantages can be obtained by using a laminated chipboard product to form long chips.

: Australian Patent No. 136.8 ^ 4. which is dated 28 March 1950, is one of the earlier descriptions relating to the manufacture of timber from particles. The particles recommended in this patent are sticks, sticks, etc. which are oriented in the longitudinal direction of the timber and ____ are fastened together. Czechoslovak Patent No. 93,154, issued December 15, 1959 to Stofko. it has also been proposed to produce a molded product to direct 86822 racket wood parts into pieces generally defined as orophiles, such as I. U. T, L and others, including pipes and windows, and by pressing to reinforce them into a finished or semi-finished product. The instructions in this patent are described in more detail in the articles published by Stofko in Drevarsky Dyskum 2 No. 1: 81-102 (1957); Drevarskv Dyskum 5 No. 2: 2 ^ 1-261 (i960); Drevarsky Dvskum No. 2: 127-148 (1962) and Drvna Industriaja 21 (6): 104-107 (1970). In these articles, Stofko deals with panel products and timber products. iotka are presumably shaped according to his patent, and they emphasize the importance of the slenderness number, i.e. the ratio of length to thickness of wood pellets, in order to achieve the desired ones. structural properties at an acceptable density.

U.S. Patent No. 3,164,511. granted on 7 January 1965 to Elmendorf. describes a wood product made from chips about 150 mm long. width about 6 mm and thickness 0.1 - 0.5 mm. According to the applicant, commercial timber products. where you would be using a TV with such wood particles. not manufactured or sold.

U.S. Patent No. 3,956,555, issued May 11, 1976 to McKeen. describes the production of a laminated beam from a combination of directed and random wood particles in a press by depositing alternating strips of directed and random particles and then reinforcing them under pressure to form a panel and splitting the oriented strips to divide the panel into structures having directional main sections, protrusions .ia connected by a randomly directed part. which would act like an I-bar neck. This is a relatively complex structure with limited durability and suitable for use with materials.

3 86822 .the tip is directed to be loaded perpendicular to the splitting surfaces.

According to the applicant, the product described in U.S. Patent No. 4,061,819. which is applicable to the applicant of the present invention on December 6, 1977, describes the only commercially viable, usable timber product formed from wood particles (fibers). This patent describes the use of relatively long strands to obtain structural products with similar and in some cases better physical properties, including density and durability properties. than the natural wood products it replaces.

U.S. Patent No. 4,122,236, issued October 24, 1978 to Holman, describes an artificial timber product molded from chips ranging in size from £ 0 to 250 mm.

Usually when particle boards (panels) or the like are made. the density profile of the panel is such that the surfaces of the panel have the highest density and the core has the lowest density. In other words, the durability of the panel surfaces is greater than that of the core, however, since the panels are usually used with the core extending along the neutral axis of the bending moment, such a density distribution is not an important factor in determining flexural strength. It is known that the rate of pressure application in a press can be used to change the density profile with the thickness of the panel. In a continuous compression function, the rate of temperature rise along with the rate of pressure application can also be used to change the density profile with the thickness of the panel.

It is economical to produce chips because, as a rule, the chips are produced with a blade having spaced apart edges with a distance corresponding to the length of the chip to be produced, cutting substantially parallel to the sweat of the wood. In some cases, flat blades cut parallel to the wood swath are used in conjunction with spaced protrusions that cut perpendicular to the wood swing to define the length of the chips. The chips thus produced are generally relatively thin, and their width is many times greater than their thickness (the thickness being determined by the depth of cut of the blade and the width being determined by how the cutting bar of the blade bends the chip to be cut).

It is an object of the present invention to provide a timber product. formed using particle board technology and chips having an average geometry of at least 200 mm in length. a maximum thickness of a mm and a width of at least 6 mm to provide a relatively inexpensive timber product having the same or better physical properties as timber made from the same species of wood as wood chips.

Broadly speaking, the present invention relates to a particleboard product and a method of making the same, said particleboard product consisting of discrete strips of wood having a thickness E of at least 25 mm made of a single layer of wood chipboard, said chips being oriented so as to be oriented in the longitudinal direction with an average deviation of 0 to 10 degrees measured in the main plane of said p »a-gel, and an average deviation of 0 to 5 degrees measured in a smaller longitudinal path through the panel perpendicular to said main plane, said chips having an average effective length of at least 200 mm. said pieces of timber having cutting edges defining the sections of each panel, extending substantially in the longitudinal direction of said panel, said spaced sections defining the width of said timber.

Most preferably, said chips have a maximum average thickness of 4 mm and an average width of at least 6 mm.

It is preferred that said timber product has a substantially uniform density in the profile.

The present invention also relates to a method of making a timber product comprising forming a single layer panel having a thickness of at least 25 mm from a plurality of chips, orienting said chips longitudinally with respect to the longitudinal axis of said panel such that the average deviation of said chip lengths from said panel measured from the longitudinal axis in the main plane of said panel is of the order of 0 to 10 degrees and the average deviation measured in the longitudinal plane through each panel perpendicular to said main plane is 0 to 5 degrees.

reinforcing said chip formation under heat and pressure with an average effective length of at least 200 mm to apply an adhesive to coat said chips and reinforce said assembly into said panel having a substantially uniform density across the width profile, and cutting the panel in a lengthwise direction; to divide into several separate pieces of timber, the width of which is against the distance between said longitudinal cuts.

86822

It is desirable that the sputtering conditions be monitored to provide a panel with a substantially uniform density in the thickness profile.

It is desirable that the density of the timber products thus produced be in the range of 0.4 to 0.8 g / cm 3. It is desirable that the density not deviate by more than 3% from the average for the thickness of the panel.

Other features, objects, and advantages will become apparent from the following detailed description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings.

Figure 1 is a schematic sketch of a plan for carrying out the present invention.

Figure 2 is a schematic side view of the plan of Figure 1.

Figure 3 is a partial sketch view of a sheet or panel formed in accordance with the present invention and illustrates a chip layer therein.

Figure 4 is a cross-sectional view taken along line 4-4 of Figure 3.

Figure 5 is a diagram of density versus thickness and illustrates the preferred density profile with thickness through the plate of Figure 4.

Figure 6 is a cross-sectional view taken along line 6-6 of Figure 4.

The term chip, used throughout this specification, is intended to define wood particles formed by a chip cutting machine. unlike paper sawdust, '· sawdust, particles or parts cut directly from round logs or formed by cutting plywood veneer 7 86822 lua. The size of the cut chips used with the present invention, especially the length, which is always measured in the fiber direction, i.e. parallel to the longitudinal axis of the fibers, is important to provide the necessary durability to provide a replacement product for traditional timber, with substantially the same durability as the replaced timber without significant density change. .

Referring to Figure 1, glue-coated wood chips are passed through a suitable feeder to a set-up apparatus in which the chips are relatively evenly distributed laterally and then fed to a directional guide 12 (see, e.g., U.S. Patent No. 4,494,969, issued January 22, 1985 to Knudson et al. ), which orientes the chips so that their longitudinal directions are substantially parallel, as described in more detail below. In the illustrated arrangement, the mat 14 thus formed has a substantially uniform density in the width profile, and is either deposited on a base plate and conveyed to a press, such as the schematically described multi-intermediate press 16, or is conveyed by a continuous belt or the like. but to the press Ϊ6, and the mat or formation 14 is pressed and reinforced to form a panel 18, the total width of the panel being, for example, 2400 mm and the required thickness (e.g., nominally 50 mm for timber, the reinforced panel must be 38 mm thick). If a continuous press 16 is used panel 18 is continuously moving clamp 20 in the direction of 16 arrow, or chips in the longitudinal direction, which is the direction in which the wood fibers is directed to said chip, the cutting station 22. If the press 16 is not a continuous press, or it is monivälipu-cross or the like, mat 14 is transported washer lu jitettavaksi panel, the panel is removed as indicated by arrow 20, is removed from the corresponding base plate * 86 822 ".No not shown) .ia svötetään one after the other direction of the arrow 20 direction, that is, the chips longitudinal directions being directed towards the direction of the arrow 20 direction, the cutting station 22.

The schematically described cutting blade 22 is formed by a plurality of spaced apart circular saws or cutters 2a. which are axially movable through the hubs 26 on the shaft 28. The hubs 26 are conventionally mounted to be driven by the shaft 28, and yet are mounted to be axially slidable on the shaft 28 so that the position of the saws 24 can be adjusted to adjust the width of the distances between the saws. width as indicated by the panel 18 'which may be of any suitable width) with dimensions W1, W2, W3, etc. formed of wood products 30. In addition, Figure 2 schematically illustrates an automatic transmission device adapted to adjust the distance between the saws 24 and includes a shoulder pin 82. to the corresponding hub 26 and moved along the shaft 34 by a suitable guide rod 36. Each shoulder rod 32 has one guide rod 36, and each blade 24 has one shoulder rod 32 for adjusting the position of the saw 24 on the shaft 28 in a known manner. Usually the distance 2a of the saws or cutters, i.e. the widths W1. W2, etc. are greater than the panel thickness T.

The two outer blades, i.e., the top and bottom blades 24 of Figure 1, are used to flatten the panel 18 and produce flattened strips, as indicated at 38.

A suitable cutting saw, schematically indicated by the number 40, passes across the panel 18 after. ' ‘The appropriate length of the blades 30 to be cut has passed the saws: ·. 2a, to cut the plates to the desired length. In the continuous operation, the saw a0 travels in both the transverse and longitudinal directions so that the square section is the width of the panel 18 (see arrows 42 and 44 in Figure 1), and when separate panels 18 are formed with washers, a cutting room may not be necessary but may be useful for smoothing the length.

It is intended that the press 16 be used as described above to obtain a panel 18 which has sufficient strength and which requires the use of chips with an average length of at least 200 mm (length always measured in the direction of the chip causes) and most preferably 250-600 mm . Usually, such chips are cut so that their average thickness does not exceed 4 mm and is most preferably less than 2.5 mm, with thicker chips usually being used to produce a thicker panel. It is desirable that the average width of the chips be at least 6 mm, most preferably at least 12 mm, and in many cases the ratio of width to thickness is between 10.

The chips must be oriented in such a way that their longitudinal direction is parallel to the longitudinal direction of the timber, which. as indicated above, is formed by cutting substantially parallel to the longitudinal direction of the panel 18 or parallel to the exit direction · /; *: from the compression 16. This orientation is never the same. in the machine direction, i.e. parallel to the longitudinal axis of the panel 18 and the axial length of the timber products 30, but is such that the average deviation of the chip lengths (fiber direction) from the longitudinal axis of the panel 18 and thus the longitudinal axis of the timber product is about 0-10 degrees from the upper surface of the panel 18, as indicated by 46 in Figures 2 and 3. The average deviation measured in a plane extending longitudinally with respect to the panel 18 or the levers 30, for example parallel to the intersecting surfaces formed by the saw blades 24 (i.e. perpendicular to the plane). , is usually of the order of 0 to 5 degrees, as schematically illustrated by angle A in Figure 4. It is desirable that angle A be small closer to 0 to 3 degrees, because if angle A is too large and chips extend almost from one main surface of the panel to another, heikk o product, and this should be avoided.

The compression cycle is adjusted (including the rate of temperature change in a continuous press) depending on the product produced, but is usually such that the density in the thickness profile is substantially constant, i.e. the deviation is less than 3% of the average in a standard timber product. Generally, the surfaces of the panel 18 that communicate with the compression plates have a slightly higher density than the center of the panel. If the timber product is to be used for boarding, i.e. the load is applied perpendicular to the main surface, it may be advantageous to produce a panel with separate core and surface layers. with the surface layers having a significantly higher density than the core. In a board, the deviation of the density from the average can be as large as 10% depending on the relative thickness of the density surface layers compared to the less dense core parts.

The uniform density profile versus thickness is much more important in the structural timber product of the present invention, which is usually loaded perpendicular to its cutting or edge surface, i.e. parallel to the surface represented by the surface 18 of the panel 18 such that the main surfaces of the panel in contact with the press plates are parallel. like the load, ia the center of the panel or vdin no longer forms a neutral axis when the structural part is compressed.

1α. 86822

In the operation of the present invention, suitable chips, as described above, are first formed into a mat IA that is on average A times thicker than the desired final thickness of the panel 18, which usually limits the maximum possible thickness of the panel to about 100 mm. The chips are pre-coated with an adhesive, usually a phenol-liformaldehyde resin, although isocyanate or any other suitable adhesive may be used. Generally, if phenol formaldehyde is used, a dried, powdered resin is used, although a wet or liquid resin may also be used in a suitable application. Changing the resin may require changing the compression schedule to ensure proper vulcanization of the resin when the mat is under pressure.

Assuming that the timber to be produced is nominally 50 mm thick timber, the thickness of the panel 18 is AO mm and the cutters 2A are separated to cut the panel 18 into strips and produce 50 x ISO, 50 x 200, 50 x 250. 50 x 300 or even 50 x A00 mm, etc. if desired. In general, the greater the width, the more valuable the product, although it is as easy to make a 50 x 100 mm sheet as a 50 x 100 mm sheet using the present invention, and any product blend can be prepared. a continuous press is used, the length of the boards thus formed is simply determined by activating the cutting saw AO to cut the boards to the desired length.If washers, the saw AO can simply be used to smooth the timber to the correct length or alternatively it can be smoothed at some other stage.

Example 1

The single-layer, oriented chip mat consisted of hand-cast aspen nude with a 2A00 mm long washer.

ΐ2 86822 The shredded chips were 300 mm long. 0.6 mm thick and 30 mm wide, and were produced in MacMilla’s Bloedel’s Thunder Bay Division. 5% ground phenol tormaldehyde dihydrate and 2% compressed paraffin were applied to the chips. An equal 2400 mm washer was placed on the mat before pressing. The padded mat was then passed through a hot press (in a research center under laboratory conditions) 600 mm at a time. Each site was pressed for 20 minutes at a pressing temperature of 210 ° C. The thickness of the resulting product was 380 mm. and 1) its average density was 0.64 g / cm 2. Thus, the modulus of elasticity of a part of the product was 11.70 GPa measured when a force is applied parallel to the surfaces formed by the washers, i.e. in a direction corresponding to a direction perpendicular to the cutting surfaces of the timber product.

It is obvious that the pressing of this sample did not take place under ideal conditions, so the panel produced was far from ideal. However, the sample clearly shows that the modulus of elasticity at least corresponded to the modulus of elasticity of conventional timber of defined quality at a reasonable density.

Example 2

In another attempt to determine the usefulness of utilizing relatively inexpensive chips, a relatively thin aspen chip having a thickness of 1 mm 10 7 »at moisture content. cut to a length of 300 mm. 10 mm wide strips 2400 mm long, 280 mm wide and 60 mm thick. to make a directional wood billet using continuous compression, microwave heating, 6% ground phenol formaldehyde resin and 2% compressed oaraffin. The mat was formed from chips pre-coated with glue and oriented to be substantially parallel to the longitudinal direction of the timber product and passed through a press for 9 minutes to 86822 13 tin a.ian. The actual specific gravity of the resulting wood product was 0.64 g / cm -1 at 12% humidity, and the average modulus of elasticity of the resulting board was 11.22 GPa. and its modulus of fracture was 46.92 MPa.

The second sheet made in the same way had a specific gravity of 0.54 U / cm -1 and a modulus of elasticity of 10.2 GPa and a modulus of fracture of 37.4 MPa.

Examples 1 and 2 clearly show that it was useful to make timber products. having acceptable physical properties for structural timber applications. when made from a wood species, such as a wound, which is not a good wood species for such materials, and with a final density greater than that of the wound and similar to that of several wood species.

After the description of the invention, the modifications will be apparent to those skilled in the art without departing from the spirit of the invention as defined in the appended claims.

Claims (6)

A chipboard timber product with a thickness of at least about 25 mm and formed of a panel made of wood chips, these chips being oriented so that their average longitudinal deviation from the longitudinal axis measured in the main plane of the panel is of the order of 0-10 ° and the average deviation measured from a lateral plane extending in the longitudinal direction of the panel and perpendicular to said main plane is 0-5 °, characterized in that said chips are formed by a chip cutting machine, the thickness of the chips is less than 2.5 mm, the width is at least 12 mm, the width to thickness ratio is more than 10 and the average length of the chips, measured in the direction of the causes of the chips, is at least 200 mm, that said timber product has two cutting edges spaced apart to define the width of the wood product and that the cutting edges extend substantially parallel to the panel the macaw is cut, said longitudinal axis. Timber product according to claim 1, characterized in that said timber product has a density of the order of 400-800 kg / m 2. Timber product according to claim 2, characterized in that said chips have a thickness of less than 1.25 mm. Timber product according to claim 3, characterized in that the average length of said chips is between 250 and 600 mm. Timber product according to Claim 3, characterized in that it has a substantially uniform density in the thickness profile. Timber product according to Claim 3, characterized in that it has a density profile with a thickness such that the deviation from the average density is less than 3%. 15 86822