DESC:Field of the invention
The present invention relates to the process of making writing articles such as pencils, the composition for the purpose of making the same and the writing article made there from.
Background of the invention and prior art
The present invention envisages an economical and a simple process to make superior writing articles desired by the consumers. Freshly cut or "green" wood per se may not be preferred in pencil making industry since fresh wood has high moisture content and would be subject to attack by wood borers and micro flora. This poses a major threat to the durability and life of the pencil. It also causes dimensional instability to the pencil. Hence freshly cut wood cannot be used as such and hence appropriate treatment process holds the key. Selecting the right wood material and processing them to manufacture the writing articles with acceptable standards, sell them at affordable prices remains challenging. For pencil making, the wood material must have uniform wood traits including good stem form, less knots due to self-pruning ability, even grains for sharpening ease and tolerance to a wide range of soil and climatic conditions. Good stem form gives higher conversion rate; few knots help in better sharpening ease and ability to tolerate different environmental conditions enable good stem form and uniform wood traits.
For instance, certain wood (low to medium density wood) retards penetration of chemicals and affects the sharpening quality of the pencil. Pencils made out of any unacceptable traits may not give the desirable and pleasing tint. There are some other factors like proper waxing which are required in order to ensure smooth sharpening quality of any pencil. Further, coloring of the pencil is yet another factor wherein consumer readily relates them to the quality. For example, pencils made out of plantation woods that are fast grown and have low to medium density which has a dark colored heartwood which does not give proper aesthetic look to the product as consumers rate them as undesired. Further, warping is yet another problem associated with the pencil making process. Upon drying, the wood material tends to bend due to stresses and shrinkage from the uneven drying of lumber is defined as warping.
Various attempts have been made to address all these concerns. For instance, US 2907684 (herein after referred to as ‘684) relates to a method for altering the cutting qualities of incense cedar pencil wood to render it easier to process with saws, planers and other wood cutting tools. However, '684 use polyethylene glycol with molecular weight of atleast 6000 and a melting point of 60°C which is not preferred in the immediate invention. Further it is an improvisation of US 1942146 which teaches the use of polyethylene glycol with a molecular weight of 2000-3000. Hence such softening methods are cumbersome and may not be suitable for making good pencils and also amounts to additional process steps with longer time.
US 997275 (herein after referred to as ‘275) relates to a process for treating wood for use in pencils, consisting immersing it in hot dilute sulfuric acid until a reddish tint is produced and afterward impregnating the same with a regulated quantity of liquid paraffin wax at a temperature slightly above the boiling point of Water. However, addition of sulfuric acid is an age old process, and very complex which needs a very careful attention and not user-friendly.
US 1699635 (herein after referred to as ‘635) relates to an improved method of and means for seasoning and softening wood of varied kinds which are not naturally suitable for use in the manufacture of lead and like pencils, and by such treatment render the wood particularly adaptable for such manufacture. '635 utilizes a very different and tedious process such as vaporization of the softening material. This would consume lot of time to make the product and expensive too.
Further prior art discloses various other applications of Acacia species. For instance, JP 4860466 related to manufacture of particle, JP 2007136876 related to Laminated composite wood material and JP 2004352639 relates to active oxygen scavenger and its composition.
Hence there is a need for improved composition as well as improved and economical process for making writing articles and the writing article made there from which provides a superior quality and at the same time prohibits the tendency of the wood to warp and uniformly impregnate the dye to impart the color to the pencils.
Objects of the invention
It is an object of the present invention is to provide a process of making writing articles as defined in the present invention.
Another object of the present invention to provide the writing articles made out of wood materials, preferably, a fast grown, low to medium density wood species.
It is another object of the present invention to provide the writing articles made out of wood materials selected from the list including but not limited to Acacia mangium, Alstonia scholaris, Anthocepahlus cadamba, Polyalthia longifolia, Populus deltoides, P.fremonti, P. nigra, Cedrus deodara, Macaranga peltata and a combination thereof, with a density of 0.3 to 0.6 g/c.c., modulus of elasticity (MOE) around 3000 to 12000 N/mm2, strength of about 30-90 N/mm2.
Another object of the present invention is to prevent warping of the wood material to be used in pencils.
Yet another object of the present invention is to provide a composition for the treatment of the wooden article of the present invention to achieve said desired properties of density of 0.3 to 0.6 g/c.c., modulus of elasticity (MOE) around 3000 to 12000, strength of about 30 to 90 N/mm2,
Another object of the present invention is to provide uniform dye impregnation to impart the color to the pencils.
Yet another object of the present invention is to provide quality writing articles with acceptable torque value in the range of 20 N/mm2 to 70 N/mm2.
Brief Description of the Accompanying Drawings
Fig 1 Wood material (Acacia mangium) showing the dye has not been impregnated using the conventional process and also shows wood warping.
Fig 2 Wood material (Acacia mangium) treated with the present composition, shows zero or reduced warping with uniform dye impregnation.
Fig 3: Before the treatment process using 10000X SEM image for A. mangium wood slat
Fig 4: After the treatment process using 10000X SEM image for A. mangium wood slat.
Fig 5: Wooden slat made from Macaranga peltata (Vatta) showing poor dye impregnation, with warping issues (Negative example)
Fig 6: Wooden slat made out of Macaranga peltata (Vatta) showing uniform dye impregnation with zero / reduced warping (present invention)
Fig 7: Wooden slat made from A. mangium showing poor dye impregnation, with warping issues (Negative example)
Fig 8: Wooden slat made out of A.mangium showing uniform dye impregnation with zero / reduced warping (present invention)
Summary of the invention
An aspect of the present invention provides a composition for treating of wooden slats for writing articles comprising
a. wax emulsion, preferably in the range of 0.1-25%;
b. organic solvent as a carrier, in the range of 0.1-30%;
c. dye in the range of 0.001-50%;
d. emulsifier, in the range of 0.5-5; and
e. pH stabilisers in the range of 1-30
Another aspect of the present invention provides a process of treating wood slats comprising steps of:
a. Load the moist/ dry Slats into pressure vessel around 100-200 psi;
b. Load the wax and dye composition as claimed in claim 1 into the chamber with vacuum;
c. Release the vacuum and apply pressure of 100-200 psi for a minimum of an hour at 80-100 °C;
d. Drain the unused wax and dye composition into the Storage drum;
e. Natural seasoning of treated slats to minimum moisture content with 20%.

Detailed Description of the present Invention
The present invention relates to process of making writing articles such as pencils and the composition used for the purpose therein and does not claim the inherent properties of the wood species. Whereas the challenges of the present invention is to make writing articles of desired quality from a wood material which has the specified parameters such as MOE, density and strength. The MOE, strength, density of the wood materials plays a vital role in accomplishing the quality of pencils. The writing articles of the present invention is made out of the wood material that has a density of 0.3 to 0.6 g/c.c., modulus of elasticity (MOE) around 3000 to 12000 N/mm2, strength of about 30-90 N/mm2. Further the preferred wood materials are selected from Acacia mangium, Alstonia scholaris, Anthocepahlus cadamba, Polyalthia longifolia, Populus deltoides, P.fremonti, P. nigra, Cedrus deodara, Macaranga peltata and combinations thereof.
Such parameters alone does not attribute towards the quality of the writing articles. For instance, the wood materials with high density are not desirable because naturally the 'porosity' of the wood material would be less and hence it is highly impossible to subject the same for further treatment process. Whereas if the wood material having low density, the problems associated with such material is "warping" which is commonly known as "bending of wood" which is highly unacceptable in pencil making industry. Further such wood materials may not be of any use in subjecting them for further treatment processes. It has to be further treated to make it suitable to achieve the quality parameters. The present invention also contemplates the composition for the treatment of wood material for writing articles comprising, wax emulsion, preferably in the range of 0.1-25% by wt, more preferably, 0.5-10% by wt; organic solvent as a carrier, in the range of 0.1-30% by wt, dye, in the range of 0.001-50% by wt, preferably 0.1-10% by wt.
It has been found by the inventors that when the parameters of wood materials such as density, MOE, strength etc. are treated with the composition of the present invention, improved results with respect to torque value, uniform dye impregnation, zero or reduced warping etc are obtained.
To make pencils, the very first criteria is to select the right wooden materials with desired parameters like density, MoE and strength. In other words, not every wooden material will be suitable for making pencils e.g. Silk Cotton wood, White mutti etc. are undesirable. The draws backs for not using them is that they are deemed to be “weak” according to any pencil making standards, also has less half-life and prone to insect infections which makes them less attractive in the pencil industry (example 5, table 5). The other disadvantages are the ‘heterogeneity’ which leads to undesirable variations in the final product. This affects the final product (pencils) and their sharpening ability, measured by torque value.
Some of the other wood materials used in the present invention are selected from a fast grown, low to medium density wood species, e.g. Acacia mangium, Alstonia scholaris, Anthocepahlus cadamba, Polyalthia longifolia, Populus deltoides, P.fremonti, P. nigra, Cedrus deodara, Macaranga peltata and a combination thereof.
It has been found by the inventors that, any wood material which has the desired characteristics vis-à-vis MoE, strength and density as illustrated in table 5 would be suitable. In this context, all the above said species possess such desired characteristics, and hence shortlisted for making writing articles. But they cannot be used in its natural form. The inventors have demonstrated the working efficiency of the composition in Acacia, and Macaranga (Vatta) species to make them suitable for writing articles. This may be extended to other wooden materials as well.
Figures are provided to show that the unique composition to treat any wood material, (e.g. vatta, A. mangium etc.) with a density of 0.3 to 0.6 g/c.c., modulus of elasticity (MOE) around 3000 to 12000 N/mm2, strength of about 30-90 N/mm2 which aids in uniform wax, dye impregnation and zero/reduced warping as illustrated in figures 5-8.
“Treated” wood as per the present invention can be defined as a wood material that has undergone chemical modifications.
“Fast grown” wood as per the present invention can be defined as a plantation wood that can be grown within a time span of 10 years and most preferably within 5 to 8 years.
“Low to medium density wood” as per the present invention can be defined as those species that come in a range of 0.3 to 0.6 g/c.c based on a classification of species with wood density less than 0.35 g/c.c categorized as low density, between 0.35 and 0.50 g/c.c as medium density and above 0.50 g/c.c as high density wood.
"Torque value" within the meaning of the present invention can be defined as a measure of sharpening quality. If the torque value is 20 N/mm2 the wood is very soft. Further if the torque value is more than 70 N/mm2, the wood is hard and not easy to sharpen.
"Dye" can be defined as any solution which imparts color in the pH range of 7 to 14, and in the present invention is selected from azo dyes. Dye is imparted to the wood material.
"pH stabilizers" used in the present composition is selected from sodium hydroxide, potassium hydroxide, ammonium hydroxide or the like.
Dye color plays a crucial role in the writing articles. Wood material without a dye would have various shades (non-uniformity) and consumers readily connect them to the quality of the pencils, which is technically incorrect. Hence to overcome such hurdles it is also challenging to choose the right dye material which can impart uniform color to the slats and eventually made into pencils of desirable quality.
An embodiment of the present invention provides a process for preparation of the composition of the present invention which is used for the treatment of wood to provide the writing article of the present invention:
Process of waxing and dyeing (with acidic and basic conditions):
Preparation of Dye solution:
In 500 liters of boiling water 0.001 to 50% dye is added and stirred properly until homogenous solution is achieved. At room temperature, the solution is diluted with 500 liters of cold water. In this stage, solution is in an acidic condition (pH between 2 to 6.5).
Preparation Wax emulsion:
In 1000 liters of boiling water required amount of wax is added, preferably 0.5 to 10 wt%, and stir properly until it becomes homogenous emulsion. Add wax emulsion comprising surfactants, in an amount of 0.5 - 5% is added and stirred. At this stage, pH stabilizers such as ammonium hydroxide are added as quantity sufficient (qs), depending on the requirement of viscosity and pH. pH is maintained in the range between 7 to 12, preferably 8.
Preparation of wax and dye solution:
Once the homogeneous wax emulsion and dye solution is prepared, both the solutions in appropriate amount are mixed. The amount of wax emulsion used is 0.5 to 10 wt% and dye solution is 0.001 to 50 wt %. After mixing wax & and dye, add 0.1 to 30 % of organic solvent such as alcohols, acetone, dimethlyl sulfoxide (DMSO) (optional) which acts as carrier for the dye and wax impregnation process. In this stage pH is maintained at acidic/basic conditions respectively for higher dye/wax penetration amounts.
Another embodiment of the present invention provides a composition for the treatment of A. mangium comprising: Organic solvent; Dye solution; pH stabilizer; Wax; Emulsifiers; and Surfactants.
The organic solvents can be chosen from alcohols, acetone, dimethlyl sulfoxide (DMSO). The amount of organic solvents ranges from 0.1 to 30% wt.
"Dye solution" can be defined as any solution which imparts color in the pH range of 7 to 14, and in the present invention is selected from azo dyes. The amount of dye ranges from 0.001-50% dye
Wax is chosen from a group comprising all commercial grade waxes. The amount of wax ranges from 0.5 to 10% wt.
Surfactants are selected from organic fatty acid, such as stearic acid, and emulsifiers such as fatty acids, fatty alcohol, and polysiloxanes. The amount of surfactants ranges from 0.5 - 5%.
pH stabilizers are selected from sodium hydroxide, potassium hydroxide ammonium hydroxide or the like in an amount of pH stabilizers and used as quantity sufficient (qs).
Emulsifiers are chosen from the group comprising fatty acids, fatty alcohol, and polysiloxanes. The same are present in the composition of the present invention ranging from 0.5-5 % wt.
Yet another embodiment of the present invention provides a process of wax and dye loading into Acacia mangium slats:
1. Load the moist/ dry Slats into pressure vessel around 100-200 psi, preferably, 120 psi
2. Load the wax and dye composition into the chamber with vacuum.
3. Release the vacuum and apply pressure of 100-200 psi for a minimum of an hour at 80-100 °C
4. Drain the unused wax and dye composition into the Storage drum
5. Natural seasoning of treated slats to minimum moisture content with 20%.
Optionally, the dye and wax treatment can happen separately for 3 hours each before they are subjected to natural seasoning.
Figure 3 which illustrates an image for A. mangium wood slat before the treatment process using 10000X SEM clearly depicts the 'pore' still remains wide open, which is undesirable to make writing articles. The most challenging aspect is in selecting the right wood material and design the parameters such as MOE, strength and density and further subjecting them to a treatment process.
Figure 4 illustrates 10000X SEM image for A. mangium wood slat after the treatment process. The figures clearly demonstrates that it’s the unique composition along with the treatment process which makes the pores of A. mangium glued with the composition makes the writing articles of superior and desired quality. For instance pencil of the present invention has the torque value of 20 to 70 N/mm2.
The present invention is now illustrated by way of non limiting examples.
Example 1: Composition to treat the wooden slat of A. mangium to make the writing articles of the present invention.
Table 1
Ingredients Wt% in range Exact Wt%
Organic solvent 0.1 - 30 5
Dye 0.001 - 50 5
pH stabiliser 1 - 30 10
Wax 0.5 - 10 10
Emulsifiers 0.5 - 5 2

Results and observations:
Wood material (Acacia mangium) treated with the present composition, shows zero or reduced warping with uniform dye impregnation as also evident from figure 2.
Beyond the range, it becomes saturated and unable to use further. This also affects the wax, dye penetration and thereby affects the sharpening effect of the pencils and also gives warping/bending. This is substantiated by the torque value which should be between the range of 20-70 N/mm2 (refer table 3).
Example 2: By using conventional process which does not involve organic solvents, dyes to treat the wooden slats of A. mangium, the results are undesirable. (Negative example)
Table 2
Ingredients Exact Wt%
Organic solvent 0
Dye 0
pH stabiliser qs
Wax 10
Emulsifiers 3

Observation: The conventional process when used not with any organic solvents and/or dye it did not yield the desired results as demonstrated in example 4.
Example 3: By utilizing the present composition, A. mangium shows acceptable quality in terms of torque value, dye impregnation and warping.

Table 3
Wood material Torque value (N/mm2) Dye impregnation (visual cue) Warping (visual cue)
Acacia mangium <50 1 1
*Indicators: 1=Acceptable quality; 0 Unacceptable quality; Torque value acceptable range (20 to 70 N/mm2).
Example 4: Negative example based on the composition described in example 2.
Table 4
Wood material Torque value (N/mm2) Dye impregnation (visual cue) Warping (visual cue)
Acacia mangium >120 0 0
*Indicators: 1=Acceptable quality; 0 Unacceptable quality; Torque value acceptable range (20 to 70 N/mm2).
Example 5: working example and negative example demonstrating the unacceptable result when wood material other than A. mangium is treated with the composition of the present invention.
Not all wood materials are preferred in pencil making industry because of the following parameters.
Table 5:
Ailanthus triphysa(White mutti)Not preferable Ceiba pentandra(Silk cotton)Not preferable Macaranga peltata(Vatta)Preferable Acacia mangium (also known as Black Wattle, Hickory Wattle, Mangium, and Forest Mangrove)The most preferable
Density g/c.c 0.3-0.6 <0.3 0.3-0.6 0.3-0.6
MoE N/mm2 <3000 <3000 3000-12000 3000-12000
Strength N/mm2 <40 <30 30-90 30-90
Results and observation: The inventors of the present invention found that any wood material e.g. A. mangium, which has the following parameters, suitable for pencil making:
1) Density of 0.3 to 0.6 g/c.c.,
2) Modulus of elasticity (MOE) around 3000 to 12000 N/mm2
3) Strength of about 30-90 N/mm2.
Once the wood materials are finalized the other challenges associated with the pencil making is to treat the wooden material with a novel composition to attain the desired characteristics of the pencil. The treatment for the wood materials become essential because the pores which are found naturally on the wood material is again a drawback for pencil making. Hence when the wooden slats are treated with the present composition, to reduce the pore size to greater extent.
Example 6: Sequential addition process for wax and dye loading into Acacia mangium slats:
Single step process of loading wax, dye into A. mangium slats:
Step A: Load the moist/ dry Slats into pressure vessel of 120 psi
Step B: Load the wax and dye solution into the chamber with vacuum
Step C: Release the vacuum and apply pressure of 120 psi for a minimum of an hour at 85°C
Step D: Drain the unused wax and dye solution into the Storage drum
Step E: Natural seasoning of treated slats to minimum moisture content with 20%
Step F: Optionally, the dye and wax treatment can happen separately for 3 hours each before they are subjected to natural seasoning.
Result and observation: the composition parameters listed in the above examples alone does not attribute towards the quality of the writing articles. For instance, the wood material with high density is not desirable because naturally the 'porosity' of the wood material would be less and hence it is highly impossible to subject the same for further treatment process. Whereas if the wood material having low density, the problems associated with such material is "warping" which is commonly known as "bending of wood" which is highly unacceptable in pencil making industry. Further such wood materials may not be of any use in subjecting them for further treatment processes. It has to be further treated to make it suitable to achieve the quality parameters. The sequential steps of the process is detailed in example 6. If the sequence and the parameters are not followed, it would result in making quality pencils which affects the torque value. Further the poor wax and dye penetration leads to warping / bending of wood.
,CLAIMS:1. A composition for treating of wooden slats for writing articles comprising
a) wax emulsion, preferably in the range of 0.1-25%;
b) organic solvent as a carrier, in the range of 0.1-30%;
c) dye in the range of 0.001-50%;
d) emulsifier, in the range of 0.5-5; and
e) pH stabilisers in the range of 1-30
2. A process of treating wood slats comprising steps of:
a) Load the moist/ dry Slats into pressure vessel around 100-200 psi;
b) Load the wax and dye composition as claimed in claim 1 into the chamber with vacuum;
c) Release the vacuum and apply pressure of 100-200 psi for a minimum of an hour at 80-100 °C;
d) Drain the unused wax and dye composition into the Storage drum;
e) Natural seasoning of treated slats to minimum moisture content with 20%.
3. The process as claimed in claim 2, wherein said treated slats of step (e) have a density of about 0.3 to 0.6 g/c.c.
4. The process as claimed in claim 2, wherein said treated slats of step (e) have a modulus of elasticity (MOE) in the range of 3000-12000 N/mm2.
5. The process as claimed in claim 2, wherein said treated slats of step (e) have a strength of about 30-90 N/mm2.
6. The process as claimed in claim 2, wherein said treated slats of step (e) have a torque value of 20 to 70 N/mm2.
7. The process as claimed in claim 2, wherein said the moist/ dry Slats of step (a) is of wood material selected from but not limited to Acacia mangium, Alstonia scholaris, Anthocepahlus cadamba, Polyalthia longifolia, Populus deltoides, P.fremonti, P. nigra, Cedrus deodara, Macaranga peltata and a combination thereof.
8. The process as claimed in claim 7, wherein said wood material is preferably, Acacia mangium.