GB2342614A

GB2342614A - Moulding process

Info

Publication number: GB2342614A
Application number: GB9821822A
Authority: GB
Inventors: Joseph Roukin
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-10-05
Filing date: 1998-10-05
Publication date: 2000-04-19
Also published as: GB9821822D0

Abstract

A composition to be used in a moulding process comprises a resin, a catalyst, and sawdust and/or wood shavings and/or metal filings. The composition is pre-mixed prior to adding it to a mould and then allowing it to cure. The composition may optionally also include at least one ink dye for the sawdust/wood shavings. The resin may be a thixotropic orthophalic polyester resin or a phenolic resin. The catalyst may be methyl ethyl ketone peroxide. The moulding process is preferably compression moulding.

Description

PROCESS FOR THE MANUFACTURE OF A PRODUCT The present invention relates to a process for the manufacture of a product. More particularly, the present invention relates to a process for the manufacture of a product which can be used to construct floor coverings, room fittings, work surfaces, furniture, boats, canoes, jewellery, i. e. any product, the shape of which is determined by a mould.

The present invention also provides a product when made by the process of the present invention, as well as the product per se.

Brazilian Patent No. P 18952137-OA discloses a process for the manufacture of a product for the construction of floor coverings, slabs etc., made from a mixture of wood shavings, sawdust and phenolic resin.

Such process comprises the steps of selecting the wood shavings by their colour, solidness and content of natural resin, and mixing the wood shavings with sawdust at a ratio of 65%: 35% respectively. The resultant mixture is then homogenised and impregnated with a natural phenolic resin in the ratio of 60%: 75% to 25%: 40% respectively. The impregnated mixture is then allowed to dry for approximately 24 hours, and the dried impregnated mixture is then moulded and heated to a temperature of approximately 120 to 140 C for 4 to 7 minutes. The resultant product is then removed from the mould and ready for use.

The problem associated with such a process is that it is extremely time consuming and moreover, and since the application of heat is required, consumes a lot of energy.

According to the present invention there is provided a process for the manufacture of a product comprising the steps of: preparing a composition comprising a selected amount of resin, catalyst and sawdust and/or wood shavings and/or metal filings; adding the composition to a mould ; and leaving same to cure.

It is an object of the present invention to provide a process that is believed to overcome, or at least address, the problems outlined above. In particular, the process of the present invention is less time consuming and hence, more efficient, and moreover, does not require the external application of heat during moulding.

The present invention will now be exemplified in a non-limiting manner, with reference to the following examples: Example 1 a) A particular type and grade of sawdust and/or wood shavings were selected.

Different grades and textures can be obtained by using different types of machinery, for example, a sanding machine will produce fine sawdust, whereas, a plane, lathe or drill will produce wood shavings at different grades depending upon the different heights, shapes and sizes of the cutting tools used. Furthermore, different types of wood will affect the grades and textures of the sawdust and/or wood shavings produced.

In a preferred embodiment, the sawdust and/or wood shavings are produced from chipboard, MDF, plywood, ash, apple, beech, jellutong, mahogany, pine, red wood and yew. It is to be understood that the sawdust and/or wood shavings can be produced from a single type of wood, or a combination of wood types. b) Preferably the sawdust and/or wood shavings selected were then dyed to a desired colour using ink dyes, preferably, permanent ink dyes.

In order to dye 250 grams of wood shavings, preferably fine wood shavings, 250 grams of wood shavings, produced from beech, were placed into a container, preferably a clean plastic container, and 400 millilitres of water and 100 millilitres of permanent ink were placed in a separate container and were mixed using a stirring apparatus, for example, a stainless steel or plastic spoon.

The mixture of water and ink were then placed into the container containing the wood shavings, and mixed using a stirring apparats. It was observed that the wood shavings would absorb most of the liquid added. Excess liquid was then removed from said container and the contents of the container were then placed onto a baking tray and spread evenly. The baking tray was then placed into an oven, for approximately 45 minutes, at a temperature of approximately 350 C. This dried the dyed wood shavings.

The skilled person would realise that the temperature required is dependent on the size of the oven, the type of wood to be dyed and the size of the wood shavings to be dyed. c) A desired type and grade of metal was then selected.

Different grades of metal can be obtained by using industrial machinery, for example, a milling machine or engineering lathe. The skilled person will realise that the speed of such a machine and the sharpness of the cutter provided on said machine, will determine the grade. For example, a machine run at high speed having a sharp cutter will produce a fine grade of metal. Additionally, the skilled person will realise that the type of metal used will also affect the grade, since some metals are harder than others.

For example, brass is harder than silver and aluminium. In a preferred embodiment, the metal selected was aluminium, brass or silver. It is to be understood that either a single type of metal may be selected, or a combination of metals may be selected. d) A mould, was selected, the shape of which determines the shape of the object to be made. The male part of said mould was covered with a releasing agent. In a preferred embodiment, the releasing agent is beeswax or liquid PVC. e) A layer of white petroleum jelly was then spread over, or applied to, the releasing agent.

An amount, enough to cover the surface of the male mould, of resin was then placed into a container.

In a preferred embodiment, the resin is a pre-accelerated low viscosity, thixot, zpic, orthophalic polyester laminating resin. Further preferably, the resin is Beetle General Purpose Polyester Resin 864E.

A suitable catalyst, preferably, methyl ethyl ketone peroxide (MEKP), was then acded and mixed with the resin, preferably, utilising a non-plastic implement, for example, a wooden stick. Further preferably, 1-2.5wt% of MEKP was added to the resin. g) A thin layer of the resin and catalyst composition was then applied to the surface of the male mould.

In a preferred embodiment, the thin layer of the resin and catalyst composition is applied utilising a paintbrush having PVC bristles. h) The selected sawdust and/or wood shavings, and/or metal filings were then sprinkled onto the male mould, that is, until such time as the surface thereof is completely or partially or substantially covered with said wood shavings and/or sawdust and/or metal filings. The amount added depends on the desired look of the finished product.

If sawdust is used, then the sawdust must be completely saturated with the resin. i) The resin was then left to cure.

This took approximately 15-50 minutes and is dependent on the percentage of the catalyst used, as well as on the catalytic properties of the catalyst used. j) Whilst the mixture of resin, catalyst and wood shavings and/or sawdust and/or metal filings on the male mould was curing, a female mould was then prepared in accordance with steps b) to e), as outlined above. k) An amount of resin, that is, enough to completely saturate the metal and/or wood shavings and/or sawdust utilised was then poured into a container, preferably a PVC container.

I) A suitable amount of catalyst was then added to said resin. In a preferred embodiment, 2wt% of MEKP was added to the resin. Once again the mixture of resin and catalyst is then mixed, preferably, using a non-plastic implement, for example, a wooden stick. m) A thin layer of the resin solution was then applied to the surface of the male mould using a paintbrush, preferably having PVC bristles. n) The sawdust and/or wood shavings and/or metal filings was then poured into the rest of the resin solution and stirred with a non-plastic implement, that is, until the sawdust and/or wood shavings and/or metal filings was completely saturated and mixed. The resultant composition was then poured into the female mould and the male mould was then firmly pressed into the female mould, that is, with a view to removing any air pockets therefrom. Additionally, the mould could be agitated with a view to removing any air-pockets. The male mould was then secured into position using locators and held under pressure by, for example, a 10Kg weight. o) The composition within the mould was then left to cure for approximately 50 minutes. The time being dependent on the amount of catalyst added, as well as the catalytic properties of the catalyst used. p) After curing, the moulded product was removed from the mould and then left to cure completely and cool for approximately 3 to 4 hours. q) The resultant moulded product was solid and was ready for finishing.

Finishing The moulded product can be finished in several ways depending upon the surface texture desired.

If a texture finish is desired, then, and because a chemical reaction occurs between the resin solution and the white petroleum jelly which produces a wrinkled, textured surface, all that is required is to simply brush the moulded product utilising a wire brush, preferably a stiff wire brush.

If a polished finish is desired, then various grades of abrasive paper (commonly known as wet and dry) can be used. The grades are 180,240,320,400,600,800 and 1200.

Once all these grades have been used, the material can be polished using a polishing machine. Finally, a soft cloth-polishing mop is used with polish to produce a glass-like finish. In a preferred embodiment, the polishes used are Brasso (RTM), Carborax (RTM)or Tripoli (RTM).

Regardless of the finishing treatment used, the finished moulded product is then preferably cleaned using an anti-bacterial agent, for example, Fairy Liquid (RTM) to remove all traces of polish therefrom.

Different ratios of sawdust and/or wood shavings and/or metal filings to resin can be used to determine different surface qualities. Preferably, the ratios are 55-75% sawdust and/or wood shavings and/or metal filings to 45-25% resin.

Example 2 A polished flat tile 250 mm by 200 mm by 10 mm was made by utilising 250 grams of sawdust and/or wood shavings, preferably dyed as outlined above, 600 ml of resin, 612 ml of catalyst, preferably MEKP, and a wax-releasing agent. The same method as described above was used, except that a flat mould was used and that the step including the application of white petroleum jelly was not utilised.

It is to be understood that the present invention can be utilised to produce any product or object and that it really depends on the shape of the mould used.

In a second aspect of the present invention there is provided. a product when made by the process of the present invention.

In a third aspect of the present invention, there is provided any object when made by the process of the present invention.

In a further aspect of the present invention there is provided a moulded product comprising wood shavings and/or sawdust and metal filings and a resin.

In a preferred embodiment the resin is a phenolic resin.

Claims

CLAIMS 1. A process for the manufacture of a product comprising the steps of : preparing a composition comprising a selected amount of resin, catalyst and sawdust and/or wood shavings and/or metal filings ; adding the composition to a mould ; and leaving same to cure.

2. The process of claim 1, wherein the sawdust and/or wood shavings are produced from at least one of the following types of wood selected from the group consisting of chipboard, MDF, plywood, ash, apple, beech, jellutong, mahogany, pine, red wood and yew.

3. The process of any one of the preceding claims, wherein the sawdust and/or wood shavings are dyed before preparing the composition using at least one ink dye.

4. The process of claim 4, wherein the ink dye is a permanent ink dye.

5. The process of any one of the preceding claims, wherein the metal filings are produced from at least one metal selected from the group consisting of aluminium, brass or silver.

6. The process of any one of the preceding claims, wherein prior to adding the composition to the mould, the mould is covered with a releasing agent.

7. The process of claim 6, wherein the releasing agent is beeswax or liquid PVC. 8. The process of any one of the preceding claims, wherein the resin is a pre-accelerated low viscosity, thixotropic, orthophalic polyester laminating resin.

10. The process of claim 8, wherein the resin is Beetle General Purpose Polyester Resin 864E.

11. The process of any one of the preceding claims, wherein the catalyst is methyl ethyl ketone peroxide.

12. The process of claim 11, wherein 1-2.5% wt. of methyl ethyl ketone peroxide was added to the resin.

13. The process of claim 12, wherein 2% wt. of methyl ethyl ketone peroxide was added to the resin.

14. The process of any one of the preceding claims, wherein once the composition was placed in the mould, the mould was agitated such that any air pockets within the composition were removed.

15. The process of any one of the preceding claims, wherein once added to the mould, the composition was left to cure for 50 minutes.

16. The process of any one of the preceding claims, wherein after curing, the product was removed from the mould and allowed to cool for approximately 3 to 4 hours.

17. The process of any one of the preceding claims, further including the step of finishing the product.

18. The process of claim 17, wherein finishing of the product is effected by brushing the product with a wire brush.

19. The process of claim 18, wherein the wire brush is a stiff wire brush.

20. The process of claim 17, wherein finishing of the product is effected by rubbing the product with an abrasive paper and then polishing the product.

21. The process of claim 20, wherein the product is first polished by a polishing machine and then with a soft cloth-polishing mop.

22. The process of any one of claims 17 to 21, wherein subsequent to finishing, the product is cleaned with an antibacterial agent.

23. The process of any one of the preceding claims, wherein the ratio of sawdust and/or wood shavings and/or metal filings to resin is 55-75% to 4525%.

24. The process of any one of the preceding claims, wherein the resin is a phenolic resin.

25. A process for the manufacture of a product as claimed in any one of the preceding claims substantially as hereinbefore described and exemplified.