WO2007101826A1

WO2007101826A1 - Brush structure and process for producing a brush structure

Info

Publication number: WO2007101826A1
Application number: PCT/EP2007/052015
Authority: WO
Inventors: Alessandro Nespoli
Original assignee: Nespoli Engineering Kkft
Priority date: 2006-03-06
Filing date: 2007-03-02
Publication date: 2007-09-13
Also published as: EP1996044A1; CN101394765A; ITMI20060401A1

Abstract

The brush structure comprises a handle (2) and a collar (2a) from which a plurality of bristles (3) in plastic material extend to receive varnish or paint and to release it onto a surface to be treated. The bristles (3) have their free end (4) bent to define a barrier hindering flow of the varnish or paint retained between the bristles and preventing escape of said varnish or paint from the brush. The process for producing a brush structure comprises the steps of forming a handle, a collar and a plurality of bristles and connecting the bristles to the collar and the combined bristles and collar to the handle. According to the process, the free end (4) of the bristles is permanently bent to define a barrier which hinders flow of the varnish or paint retained between the bristles and prevents escape of the varnish from the brush.

Description

BRUSH STRUCTURE AND PROCESS FOR PRODUCING A BRUSH STRUCTURE

The present invention relates to a brush structure and to a process for producing a brush structure; in particular, reference will be made hereinafter to whitewash brushes with plastic bristles.

Brushes are known to comprise a handle which can be easily gripped and manipulated by a user.

The handle carries at its end a collar housing internally a plurality of bristles which are connected together and to the collar by adhesives.

Traditionally the bristles of whitewash brushes are formed of natural materials such as animal hairs, for example pig or goat hairs, or of vegetable fibres such as tampico.

Bristles made of synthetic materials are currently becoming increasingly more widespread.

Bristles of this latter type are in the form of tubular and/or partially conical elements (solid or hollow internally) made of polyester or other plastic materials.

These bristles undergo a finishing treatment which renders them suitable for painting.

The finishing treatments consist of:

- tipping, consisting of forming a conical tip in order not to leave brush strokes on the surface being painted (a bristle treated in this manner is shown in Figure 17); - tipping and splitting the tip of a filament of mainly solid cross-section, but characterised by the presence of slits and bonding lines, obtained when the filament is undergoing extrusion. In this respect the filament is extruded in several bundles which are bonded together on exit from the die. The purpose of this treatment is similar to that of simple tipping, but the tip is softer, since the filament is broken into 4 portions of smaller dimensions (a bristle treated in this manner is shown in Figure 18);

- flagging, consisting of splitting the tip of a hollow or semi-hollow filament longitudinally (parallel to the filament axis) into several sections, to increase the surface in contact with the paint, with consequent increase in the quantity of paint collected (a bristle treated in this manner is shown in Figure 19).

However, none of the described synthetic filaments attains the performance of the pig bristle in terms of quantity of paint/varnish collected and deposited in a single cycle of operations defined by the operation of immersing the brush into the paint followed by brushing. Other attempts at varying the cross-section and finish of the filament tip have been recorded aimed at increasing the quantity of paint collected and deposited by a brush.

In this respect, US 5 032 456 teaches roughening the stems of synthetic bristles by forming craters on their surfaces. These craters are formed during extrusion by the addition of particular additives to the polymer under extrusion.

In addition, US 6 311 359 teaches the addition of mineral charges to the polymer under extrusion to create irregularities on the filament surfaces. However the results thus obtained were poor. The drawbacks deriving therefrom are evident and can be summarized as high fatigue for the operator, who is compelled to apply a very high number of brush strokes to apply a certain quantity of varnish or paint to terminate the work underway; to this must also be added the time required for painting, and hence the costs involved.

The technical aim of the present invention is therefore to provide a brush structure and a process for producing a brush structure which enable the stated technical drawbacks of the known art to be eliminated.

Within the scope of this technical aim an object of the invention is to provide a brush structure which, for each brush stroke, enables a large quantity of varnish or paint to be released, and in particular a greater varnish or paint quantity than traditional synthetic bristle and pig bristle brushes.

Another object of the invention is to provide a brush which limits operator fatigue.

A further object of the invention is to provide a brush which limits the time and cost involved in applying varnish or paint to a wall.

The technical aim, together with these and further objects, are attained according to the present invention by a brush structure and a process for producing a brush structure in accordance with the accompanying claims.

Further characteristics and advantages of the invention will be more apparent from the description of a preferred but non-exclusive embodiment of the brush structure and of the process according to the invention, illustrated by way of non-limiting example in the accompanying drawings, in which:

Figure 1 is a front elevation view of a brushr according to the invention; Figure 2 is an enlarged detail of the bristles of the brush of Figure 1 ; Figure 3 is an enlarged detail of the terminal portion of the bristles of the brush of Figure 1 ;

Figures 4 and 5 show two different embodiments of the bristles of the present invention; Figure 6 is an enlarged detail of the end of an individual bristle;

Figures 7 and 8 show a device for producing the bristles of the present invention, seen in the open and closed configuration respectively;

Figures 9-13 show some cross-sections of hollow or solid bristles;

Figures 14, 15 are a schematic view of a first device for producing the bristles of the invention;

Figure 16 is a schematic view of a second device for producing the bristles of the invention; and

Figures 17-19 show the ends of a bristle treated by tipping, tipping and splitting, and flagging respectively. With reference to the cited Figures, these show a brush structure indicated overall by the reference numeral 1.

The brush structure 1 comprises a handle 2 from which a plurality of bristles 3 extend to receive varnish or paint and to release it onto a surface to be treated; the bristles 3 are connected to the handle 2 by a collar 2a.

The bristles 3 have their free end 4 bent, to define a barrier hindering flow of the varnish or paint retained between the bristles and hindering falling of the varnish or paint from the brush 1 (for example while the brush is being carried to the wall to be painted after being dipped into the varnish). Besides being curled, the bristles are also mixed together (in the sense that the "hooks" are not all orientated in the same direction); the brush also preferably presents bristles with straight free ends of different length. In this manner the correct degree of overall curling of the brush head is achieved without excessively increasing the bristle volume.

For example, in a brush of width 50 mm (size 50), the following are mixed together:

- curled bristles of 64 mm length (30% of the total bristle weight);

- straight bristles of 64 mm length (10% of the total bristle weight); - straight bristles of 57 mm length (30% of the total bristle weight);

- straight bristles of 51 mm length (30% of the total bristle weight).

Many other mixtures are possible, differing by bristle composition and length.

Specifically, the free end 4 of the bristles 3 is bent through a circular arc of radius R between 0.5 and 15 millimetres and preferably between 3 and

12 millimetres and more preferably about 5 millimetres.

The free end of the bristles 3 is bent through a circular arc of less than

90° and preferably (in the embodiment of Figure 4) through 55-65°; specifically, they are shown bent through about 60°. Figure 5 shows a second embodiment of the bristles, with their free ends bent through a circular arc of between 25 and 35° and in particular 30°.

As shown in Figure 6, the free end of the bristles 3 is conical while in different examples is either solid or hollow; for example Figures 9-13 show some cross-sections through hollow and solid bristles. Advantageously the bristles are made of plastic material such as polyester or PET (polyethyleneterephthalate) or PBT (polybutyleneterephthalate) or Nylon 6, Nylon 6.6, Nylon 6.12, polypropylene, polyethylene; this enables bristles to be produced having a much longer life than traditional bristles.

The present invention also relates to a process for producing a brush structure 1.

The process comprises the steps of forming a handle 2 and a plurality of bristles 3 and connecting the bristles 3 to the handle 2 by means of a collar 2a.

Advantageously, according to the process, the free end 4 of the bristles 3 is bent permanently, to define a barrier which hinders flow of the varnish or paint retained between the bristles 3 to prevent escape of the varnish from the brush.

In a first embodiment of the process the end of the bristles 3 is bent by a combined mechanical and thermal treatment. This combined treatment comprises plastically deforming the bristles 3 or groups of bristles 3 in heated moulds 11 having the profile to be given to the bristles 3.

For example Figure 7 shows a mould 11 consisting of a first element 12 provided with a flat portion 13 and a portion 14 curved as a circular arc, and a second element 15 also presenting a flat portion 16 and a circular arc portion 17.

The moulds do not necessarily have to comprise a flat portion, but they must comprise a curved portion.

The flat portions 13, 16 and the circular arc portions 14, 17 can be mutually associated with the bristles 3 interposed, to plastically and irreversibly deform the bristles 3. The moulds 11 are preferably of aluminium (to achieve uniform temperature throughout the mould) and during treatment have a temperature less than 200°C and preferably 60-130°C; the most suitable temperature for each type of treatment depends on the type of bristles being treated. In a preferred embodiment the temperature is about 110⁰C.

In other embodiments the mould can be of other metals or of ceramic or other materials. What is important is that it is able to withstand the temperature required for curling the filament. In a first embodiment of the mould, only one of its two constituent parts is heated; in a different embodiment both its parts are heated. In a further embodiment (Figure 16) a roller 35 is made to rotate against the bristles in order to deform them permanently; this device preferably also comprises a mould 36 such that the bristles become closed between the mould 36 and the roller 35, a force then being applied to them.

In this embodiment at least one of the two parts (roller 35 and/or mould 36) is heated; the two parts can also both be heated. In a different embodiment of the process of the invention, the end of the bristles 3 is bent by mechanical treatment. In general, the mechanical treatment consists of permanently elongating the bristle fibres only on one of their sides, to cause permanent bending of the bristles.

This can be achieved by scratching one side of the bristles, as if curling a gift ribbon. Figures 14, 15 show a device for implementing this process. This device comprises a tool provided with a presser knife 30 which operates together with a counter-tool provided with a recessed seat 31

(however the seat could be absent).

The knife 30 makes contact with the bristles (Figure 14) and slides in contact with them (Figure 15) to deform the bristles. Advantageously, one or more filaments can be treated in a plurality of intermediate positions, these filaments then being cut such that the intermediate positions treated (and hence curved) form the free end of the bristles.

The operation of the brush of the invention is apparent from that described and illustrated, and is substantially the following.

With reference to Figure 2, when the brush is dipped into the varnish or paint the bristles (mixed after the described treatment) accumulate varnish

20; this (varnish) tends to flow along the bristles but on reaching the free end 4 of the bristles 3 cannot escape and abandon the bristles because it remains trapped by the curved ends which become interwoven to form a barrier preventing the varnish 20 from running; the varnish 20 hence remains trapped between the bristles 3 in particular at their free end 4; this hinders any falling of the varnish while carrying the brush to the wall to be painted. Modifications and variants are possible, for example the end of the bristles can be deformed with a profile different from a circular arc, for example the profile can be elliptical or otherwise.

It has been found in practice that the brush structure of the invention is particularly advantageous because it enables walls to be whitened quickly and with limited physical effort by the operator. The brush and process conceived in this manner are susceptible to numerous modifications and variants, all falling within the scope of the inventive concept; moreover all details can be replaced by technically equivalent elements.

In practice the materials used and the dimensions can be chosen at will according to requirements and the state of the art.

Claims

1. A brush structure comprising a handle from which a plurality of bristles of plastic material extend to receive varnish or paint and to release it onto a surface to be treated, characterised in that at least part of said bristles present a bent free end to define a barrier hindering flow of the varnish or paint retained between the bristles and hindering falling of said varnish or paint from said brush.

2. A brush structure as claimed in claim 1 , characterised in that said bristles with their free end bent are mixed together.

3. A brush structure as claimed in one or more of the preceding claims, characterised by also comprising bristles with straight ends.

4. A brush structure as claimed in one or more of the preceding claims, characterised in that said bristles with a straight free end have different lengths.

5. A brush structure as claimed in one or more of the preceding claims, characterised in that the free end of said bristles is bent as a circular arc.

6. A brush structure as claimed in one or more of the preceding claims, characterised in that said circular arc has a radius comprised between 0.5 and 15 and preferably between 3-12 millimetres and more preferably about 5 millimetres.

7. A brush structure as claimed in one or more of the preceding claims, characterised in that said circular arc is less than 90° in width.

8. A brush structure as claimed in one or more of the preceding claims, characterised in that said circular arc is comprised between 55-

65° in width.

9. A brush structure as claimed in one or more of the preceding claims, characterised in that said circular arc is comprised between 25- 35° in width.

10. A brush structure as claimed in one or more of the preceding claims, characterised in that said free end of said bristles is conical.

11. A brush structure as claimed in one or more of the preceding claims, characterised in that said plastic material is polyester or PET or PBT or Nylon 6 or Nylon 6.6 or Nylon 6.12 or polypropylene or polyethylene.

12. A process for producing a brush structure comprising the step of connecting a plurality of bristles to a handle, characterised by permanently bending the free end of at least part of the bristles, to define a barrier hindering flow of the varnish or paint retained between the bristles and hindering falling of said varnish or paint from said brush.

13. A process as claimed in claim 12, characterised by bending the end of the bristles by a combined mechanical and thermal treatment.

14. A process as claimed in one or more of claims 12 and onwards, characterised in that said combined treatment comprises plastically deforming bristles or groups of bristles in heated moulds presenting the profile to be given to the bristles.

15. A process as claimed in one or more of claims 12 and onwards, characterised in that said moulds have a temperature less than 200°C and preferably comprised between 60-130°C, and more preferably approximately 110°C.

16. A process as claimed in one or more of claims 12 and onwards, characterised in that said mould is made of aluminium.

17. A process as claimed in one or more of claims 12 and onwards, characterised in that the mould consists of a first element provided with a portion curved as a circular arc, and a second element also presenting a circular arc portion, the circular arc portions being able to be mutually associated with the bristles interposed, to plastically and irreversibly deform the bristles.

18. A process as claimed in claim 12, characterised by bending the end of the bristles by a mechanical treatment.

19. A process as claimed in the preceding claim, characterised in that said mechanical treatment consists of permanently elongating the bristle fibres only on one side to cause their permanent bending.

20. A process for producing bristles for brushes, characterised by permanently bending a free end of the bristles.

21. A process as claimed in the preceding claim, characterised by bending the end of the bristles by a combined mechanical and thermal treatment.

22. A process as claimed in one or more of claims 20 and onwards, characterised in that said combined treatment comprises plastically deforming bristles or groups of bristles in heated moulds having the profile to be given to the bristles.

23. A process as claimed in one or more of claims 20 and onwards, characterised in that said moulds have a temperature less than 200°C and preferably comprised between 60-160°C.

24. A process as claimed in one or more of claims 20 and onwards, characterised in that said mould is made of aluminium.

25. A process as claimed in one or more of claims 20 and onwards, characterised by bending the end of the bristles by a mechanical treatment.

26. A process as claimed in the preceding claim, characterised in that said mechanical treatment consists of permanently elongating the bristle fibres only on one side to cause their permanent bending.