WO2019017762A1

WO2019017762A1 - A method of making compreg palm wood

Info

Publication number: WO2019017762A1
Application number: PCT/MY2018/050003
Authority: WO
Inventors: Edi Suhaimi BAKAR; Mojtaba SOLTANI; Seng Hua LEE; Zaidon ASHAARI
Original assignee: Universiti Putra Malaysia
Priority date: 2017-07-17
Filing date: 2018-01-29
Publication date: 2019-01-24
Also published as: MY195808A

Abstract

The present invention relates to method of making compreg palm wood from palm species using palm trunk as its raw material. The method of making compreg palm wood is characterized by the steps sawing palm trunk to obtain a plurality of palm lumbers, segregating the plurality of lumbers into respective categories based on outer part and inner part, compressing the lumbers segregated as outer part to become a first compressed lumber and compressing the lumbers segregated as inner part to become a second compressed lumber, drying the first compressed lumber and second compressed lumber at high temperature, impregnating the first and second compressed lumber with resin, semi-curing the first and second impregnated lumber and compressing the first with second impregnated lumber by hot-pressing to obtain the compreg palm wood. The method increases the utilization rate of material, decreases the total processing time and reduces palm waste to the environment.

Description

A METHOD OF MAKING CQSVIPREG PALSVl WOOD

RELD OF INVENTION

The present invention relates to method of making compreg palm wood. More particularly, the present invention relates to a method of making compreg palm wood from oil palm, coconut palm and date palm.

BACKGROUND OF THE INVENTION

Palm wood is known to be an alternative wood material for wood products as they have non-limited supplies and are highly in demand in the lumber industry. Oil palms for example are planted almost nearly millions of hectares in South east Asia countries which makes them a good source for wood production. The physical and mechanical properties of oil palm wood and their low-cost price has also contributed them to be the main choice for alternatives of other types of timber. Coconut palm grows in moist soil worldwide, typically near saltwater and almost the entire stem of the coconut palm tree can be used to manufacture structural components, furniture and other utility articles. As a result of the long history of cultivation and utilization of date palms, almost every part of the date palm can be used for some purpose such as the trunk and wood of date palms can be used as timber, wood, or fuel. Hence, it is an essential to utilize the palm trees and at the same time the industry could decrease their dependency towards natural forest. Furthermore, natural forest such as heavy hardwood species today no longer sustains to the market demand and harvesting of this wood category would take a longer period of time, as they grow slower and will require a long time before they can be chopped off as timber. Despite palm wood's abundant supply and advantages, they require proper processing method before they can be used as solid wood for applications.

An example of method for processing wood can be found in Malaysian patent application No. PI 2014700947. The prior art discloses the method of producing compreg palm wood from oil palm using the outer parts of oil palm trunk that involves steps of debarking, sawing, compression, drying, resin soaking, heating and lastly hot-pressing. However, only the outer parts of the oil palm trunk are utilized in this prior art. This is due to the type of sawing technique employed in the prior art which is the reverse cant sawing that is only able to retrieve the outer part of the oil palm trunk. The reverse cant sawing pattern also reduces the rate of utilization of oil palm as not all of the useful oil palm parts are used In this prior art which results In higher oil palm biomass waste to the environment. Moreover, the presence of peeling step in debarking is actually an additional process before sawing that increases the processing cost. The whole process is also time consuming especially in the drying and heating steps.

Another example can be found in Japanese Publication No. 2009298132 A, which discloses an improved lumber and method of manufacturing the lumber that utilizes the oil palm stem as the raw material and treating the palm stem with a chemical treatment that involves the use of iignin for the finishing purposes. However, the requirement of Iignin in the chemical treatment for treating the palm stem did not improve the dimensional stability and machining characteristics of the palm wood. It was only able to solve the durability of the palm wood instead of other properties. Palm wood is generally known to be low quality and do not have satisfactory strength as an end product without modification of their properties. Furthermore, Iignin is expensive which makes it less favourable for wood processing.

Therefore, there is a need for improvements to the method of making compreg palm wood that addresses the above mentioned limitations of the existing method.

SUMMARY OF INVENTION

The present invention relates to a method of making compreg palm wood. In one aspect of the invention, the method of making the compreg palm wood is characterized by the steps of sawing palm trunk to obtain plurality of palm lumbers; segregating the plurality of lumbers into respective categories based on outer part and inner part; compressing the lumbers segregated as outer part to become a first compressed lumber and compressing the lumbers segregated as inner part to become a second compressed lumber; drying the first compressed lumber and second compressed lumber at high temperature; impregnating the first and second compressed lumber with resin; semi-curing the first and second impregnated lumber; and compressing the first with second impregnated lumber by hot-pressing to obtain the compreg palm wood.

Preferably, the palm trunk is sawn into a thickness between 2.5 to 4.0cm. Preferably, the step of compressing the segregated outer and inner part is conducted until similar moisture content and thickness is achieved. Preferably, the step of compressing the segregated outer part is either by using hot-press or cold-press with 20% compression level.

Preferably, the step of compressing the segregated inner part is by using hot- press with 30% compression level.

Preferably, the step of drying the compressed lumber is at a temperature ranging between 1 10 to 150°C with a target of moisture content of 20 to 40%.

Preferably, the resin is a synthetic resin.

Preferably, the synthetic resin is a low molecular weight phenol formaldehyde with 15 to 20% solid content.

Preferably, the step of semi-curing the impregnated lumber is conducted by heating at a temperature of 100°C for 3 to 4 hours to achieve a moisture content of 60 to 70%.

Preferably, the step of compressing the semi-cured lumber is performed by hot-pressing at a temperature of 150°C.

Preferably, the palm trunk is oil palm, coconut palm or date palm.

BRIEF DESCRIPTION OF THE DRAWINGS.

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

FIG. 1 illustrates a sawing technique diagram of modified cant sawing pattern. FIG. 2 illustrates a schematic diagram of compreg palm wood production. DESCRIPTION OF THE PREFERRED EMBODIMENT

A preferred embodiment of the present invention will be described herein below with reference to the accompanying drawings, in the following description, well known functions or constructions are not described in detail since they would obscure the description with unnecessary detail.

The present invention relates to a method of making compreg palm wood. This method uses palm trunk as the raw material for the process which resulted in less processing time, higher utilization rate of materials and lower production cost. Furthermore, this method allows the production of high performance compreg palm woods from low quality palm wastes in a more efficient manner and in all practicality. The method can be applied to oil palm and other palm wood species and non-woody materials such as coconut palm and date palm. Compreg palm wood is actually a palm trunk that undergoes compression and impregnation step for treatment purposes to enhance the quality of the wood as the final product. in this method the steps of sawing, compression and drying is modified to increase the utilization rate of material, decreasing the total processing time and reducing palm waste to the environment. initially, the palm trunk or log is obtained from the palm tree. For oil palm tree, the age above 25 years old is preferable which is in accordance with the industry practice whereby for other types of palm tree, must be relatively straight and have bigger diameter. The diameter of the other palm trees must be more than 30cm. The palm trunk is then sawn to obtain a plurality of palm lumbers using a sawing machine, preferably each palm lumber has a thickness in a range of 2.5cm to 4.0cm. This palm trunk is cut or sawn according to modified cant sawing pattern. Modified cant sawing is a type of sawing technique that cuts the outer part on ail sides of the palm trunk and leaving the inside or centre part into a square which is called a cant. This square cant is then sawn horizontally pieces by pieces. Other cant sawing pattern can also be used but for optimal quality, modified cant sawing in FIG. 1 is suggested. For modified cant sawing (100) the pattern is used for palm trunk with small diameter, whereby modified cant sawing (101) the pattern is used for palm trunk with bigger diameter. Both patterns have vertical and horizontal lines and the amount of lines depend on thickness of palm trunk. Most importantly, the modified cant sawing pattern must have at least one vertical line at each side of the palm trunk. By this modified cant sawing patterns, the outer and inner part of palm trunk can be easily separated and waste can be prevented as the sawing pattern is able to maximize the utilization of the most useful parts of the palm tree trunk. In addition, the peeling step can be omitted by using this modified sawing pattern resulting in less processing step and lower processing cost. On the other hand, the length for the sawn palm lumbers in this method can vary as they do not require specific measurement. Thereon, the pieces of sawn palm lumbers are segregated into two respective categories which is the outer part and inner part. Both parts normally have different moisture content with the outer part having lesser moisture content compared to the inner part. This is because the outer part of palm trunk is denser than the inner part. Then, the lumbers segregated as outer part are compressed to become a first compressed lumber and the lumbers segregated as inner part are compressed to become a second compressed lumber. The compression step reduces the moisture content and fastens the drying process. Since both parts have different moisture content, thus they have different compression technique. The outer part having a lesser moisture content is compressed by either hot-press or cold press while the inner part having high moisture content is compressed only by hot press compression. For instance, the outer part with 2.5 cm thickness having a moisture content of less than 200% is compressed at 20% compression level while the inner part with 3.0 cm thickness having a moisture content of more than 200% is compressed at 30% compression level, producing first compressed lumbers and second compressed lumbers with relatively similar final moisture content and thickness. Each part is compressed for a duration of 10 minutes. The compression for the inner part can be performed by only hot press is because the inner part requires more drying since if is high in moisture and water compared to the outer part.

Next, the first compressed lumber and second compressed lumber is sent for high temperature drying. They are dried in a kiln drier at high temperature ranging in between 1 10°C to 150°C until reaching a target moisture content between 20% to 40%. The drying is conducted without any drying defects such as splits, cracks and warping. With high temperature drying, the drying time can be shortened resulting in a faster processing time.

Thereafter, the first and second compressed lumber is subjected to impregnation step. They are impregnated for a period of 10 to 20 minutes with the synthetic resin. The resin used is low molecular weight phenol formaldehyde or Lmw- PF preferably having 15% to 20% solid content. Other resin could also be used such as urea formaldehyde, urea-melamine formaldehyde and melamine-urea formaldehyde, impregnating with resin improves physical properties such as waterproofing. Moreover, the impregnation step could also increase the durability, strength and dimensional stability of the produced compreg palm wood.

Afterwards, the first and second impregnated lumber is semi-cured by heating in an oven at approximately 100°C for 3 hours until reaching an optimal moisture content of 60% to 70%.

Finally, the first with second impregnated lumber is compressed by hot- pressing at a temperature of approximately 150°C for30 to 40 minutes to obtain compreg palm wood. The final thickness of compreg palm wood can vary according to the industrial applications. In addition, the temperature and time period required for hot-pressing mainly depends on the thickness of the palm wood and the type of resin used. The hot-pressing step also helps in the curing of resin.

While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specifications are words of description rather than limitation and various changes may be made without departing from the scope of the invention.

Claims

1. A method of making compreg palm wood is characterized by the steps of: a) sawing a palm trunk to obtain a plurality of palm lumbers;

b) segregating the plurality of lumbers into respective categories based on outer part and inner part;

c) compressing the lumbers segregated as outer part to become a first compressed lumber and compressing the lumbers segregated as inner part to become a second compressed lumber;

d) drying the first compressed lumber and second compressed lumber at high temperature;

e) impregnating the first and second compressed lumber with resin;

f) semi-curing the first and second impregnated lumber; and

g) compressing the first with second impregnated lumber by hot-pressing to obtain the compreg palm wood,

2. The method as claimed in claim 1 , wherein the palm trunk is sawn into a thickness between 2.5 to 4.0cm.

3. The method as claimed in claim 1 , wherein the step of compressing the segregated outer and inner part is conducted until similar moisture content and thickness is achieved.

4. The method as claimed in claim 1 , wherein the step of compressing the segregated outer part is either by using hot-press or cold-press.

5. The method as claimed in claim 1 , wherein the step of compressing the segregated inner part is by using hot-press.

6. The method as claimed in claim 1 , wherein the step of drying the compressed lumber is at a temperature ranging between 1 10 to 150°C with a target of moisture content of 20 to 40%.

7. The method as claimed in claim 1 , wherein the resin is a synthetic resin. 8. The method as claimed in claim 7, wherein the synthetic resin is a low molecular weight phenol formaldehyde with 15 to 20% solid content. The method as claimed in claim 1 , wherein the step of semi-curing the impregnated lumber at a temperature of 100°C for 3 to 4 hours to achieve a moisture content of 60 to 70%.

The method as claimed in claim 1 , wherein the step of compressing the semi- cured lumber is performed by hot-pressing at a temperature of 150°C.

11. The method as claimed in any of the preceding claims, wherein the palm trunk is oil palm, coconut palm or date palm.