SE542119C2 - A synthetic bristle with at least partially uneven outer surface and a paint brush having a plurality of such synthetic bristles - Google Patents

Abstract

The present invention concerns a synthetic bristle (10) for a paint brush, which synthetic bristle (10) is made of at least two different polymers, such as Polybutylene terephthalate (PBT) or Polyethylene terephthalate (PET) or Polytrimethylene terephthalate (PTT) or Polypropylene (PP) or polyamide (PA ) or Polyvinylchloride (PVC) and a Thermoplastic polyester elastomer. The invention also concerns a paint brush comprising at least a plurality of such synthetic bristles (10).

Description

A synthetic bristle with at least partially uneven outer surface and a paint brush having a plurality of such synthetic bristles TECHNICAL FIELD The present invention relates to a synthetic bristle and a paint brush comprising a plurality of such bristles.

BACKGROUND ART Paint brushes are usually made of bristles, wherein the bristles form a bristle pack or bundle or brush head, respectively, which is able to hold therein paint by adhesion as well as by capillary forces. When painting the brush head is pressed onto the surface to be painted by the hand of the operator. Thereby, the bristles are bent and the paint being held between the bristles is forced to flow out of the brush head as it is moved along the surface to be painted.

Bristles may be natural or synthetic filaments, wherein synthetic filaments, i.e. monofilaments, can be produced from a variety of thermoplastic polymers, in a variety of configurations including solid and hollow, and in a variety of cross-sections, including circular, oval, triangular, trilocular, tetralocular, lobate, or may contain multiple voids. Much work has been done in the trade to improve paint pickup and paint release of paint brushes by experimenting with blends of monofilaments of different polymers, configurations, and cross-sections, in many cases, aiming to synthetically copy or simulate features of natural fibres/filaments and their blends, e.g. by incurring split ends, bending their free ends or adding solid particles to the polymer so that craters are formed on the exterior of the filaments. In WO 2007/101826 and US 6 174600 B1, examples of such known filaments are disclosed.

SUMMARY OF THE INVENTION It is, accordingly, an object of the present invention to overcome deficiencies of the prior art, such as indicated above.

It is another object to provide an improved synthetic paint brush bristle having an improved stability while still being docile, and improved paint pickup and paint release.

It is a further object of the present invention to provide a synthetic bristle useful in the manufacture of paint brushes and giving the paint brush a docile pliability and improved stability, paint pickup and paint release.

It is a further object of the present invention to provide an improved paint brush with improved stability and pliability while still being docile, and improved paint pickup and paint release during painting.

Another object of the present invention is to provide a synthetic bristle in which at least one of the filaments comprises features that differ from prior art natural filaments or which features prior art natural filaments even lack.

These objects are achieved by means of a synthetic bristle or monofilament for a paint brush and a paint brush equipped with a plurality of such bristles or monofilaments as claimed in the associated independent claims, preferred variants thereof being defined in the associated dependent claims.

According to a first aspect of the present invention, these objects are achieved by a synthetic bristle for a paint brush, which synthetic bristle is made of at least two different polymers made by a mixture of at least Polybutylene terephthalate (PBT) or Polyethylene terephthalate (PET) or Polytrimethylene terephthalate (PTT) or Polypropylene (PP) or polyamide (PA ) or Polyvinylchloride (PVC) and a Thermoplastic polyester elastomer (TPE-E) in a ratio of between about 70 - 99% (percentage by weight, wt%) PBT or PET or PTT or PP or PA or PVC and between about 1 - 30% (percentage by weight, wt%) TPE-E, and which synthetic bristle has an at least in part substantially oval cross sectional shape or at least in part oval cross sectional shape comprising a thickness in a first dimension that is larger than a thickness in a second dimension being substantially perpendicular or perpendicular to the first dimension and thickness, wherein the synthetic bristle comprises an at least partially uneven, such as rough or rugged or ragged or irregular or bumpy or knurled or cut or pierced or teared or knocked or weared or knotty or hollow or burrowed, outer surface and wherein the synthetic bristle (10) is configured with the at least partially uneven outer surface over at least half its outer surface or not more than half its outer surface.

In one embodiment, the synthetic bristle is made of at least between about 75 - 91% PBT or PET or PTT or PP or PA or PVC and between about 9 - 25% TPE-E. In another embodiment, the synthetic bristle is made of at least between about 80 - 90% PBT or PET or PTT or PP or PA or PVC and between about 10 - 20% TPE-E. In yet another embodiment, the synthetic bristle is made of more than about 85% PBT or PET or PTT or PP or PA or PVC and less than about 15% TPE-E. In still another embodiment, the synthetic bristle is made of about 90% PBT or PET or PTT or PP or PA or PVC and about 10% TPE-E.

In one embodiment, the synthetic bristle is configured with an oval cross sectional shape.

In yet a further embodiment, the synthetic bristle is configured with the at least partially uneven outer surface on substantially half its outer surface or on approximately half its outer surface or on half its outer surface. In still an additional embodiment, the at least partially uneven outer surface of the synthetic bristle is provided with at least one or a plurality of dents and/or craters and/or holes and/or open cells.

In yet a further embodiment, the first thickness of the synthetic bristle is at least about 1.3 times larger than the second thickness or is between about 1.35 to three times larger than the second thickness, or between about 1.4 to two times larger than the second thickness.

According to a second aspect of the present invention, these objects are achieved by a paint brush comprising a handle having at one end a bristle carrier and a bundle of bristles fastened in the bristle carrier, which bristle bundle comprises at least a plurality of synthetic bristles according to the above first aspect and/or any of the preceding embodiments.

Any of the above embodiments is combinable with one or more of the other embodiments, i.e. at least one bristle according to the first embodiment is able to be mixed with at least one bristle according to any other embodiment/-s, e.g. at least one synthetic bristle made of at least between about 75 - 91% PBT or PET or PTT or PP or PA or PVC and between about 9 -25% TPE-E, and at least one synthetic bristle made of at least between about 80 - 90% PBT or PET or PTT or PP or PA or PVC and between about 10 - 20% TPE-E is possible to mix in with at least one other type of bristle in a bristle bundle, e.g. a natural or synthetic fiber made of other polymers. The same goes for the embodiments concerning the bristle shape and size, i.e. they are freely combinable with any of the other embodiments concerning bristles made of different material mixtures.

By oval cross sectional shape is meant an elongated or flattened cross-sectional shape, such as an egg shape, an ellipse shape, a broad or narrow ellipse shape, a rectangular shape having rounded corners, a cassini oval shape and the like. The oval cross sectional shape has a first axis being a longitudinal axis, and a second axis perpendicular to the first axis or longitudinal axis.

The first axis or longitudinal axis defining and/or being coinciding with the largest thickness of the synthetic bristle and the second axis defining and/or being coinciding with the largest thickness of the bristle being perpendicular to the first axis.

The first and/or second axis may each correspond to an axis of symmetry of the oval cross sectional shape.

The effect of the invention is that a synthetic bristle is provided to be mixed or blended into a bundle of bristles of a paint brush, which bundle of bristles thereby is able to be provided with an optimised orientation and positioning of each and all the bristles in relation to each other in the bristle bundle when mixed/blended and attached together in the bundle so that the paint brush is provided with an optimal painting ability by means of increased paint holding and/or storing ability minimizing the need of re-dipping the paint brush and prolonging the time before too little amount of paint is released during painting while, at the same time, giving the paint brush a paint delivery ability maximising the paint released onto a surface during painting of the surface. This increases the effective painting time for each painting stroke and minimizes the number of times the paint brush must be dipped with new/more paint. This optimises the area of effective painting surface of the paint brush by optimising the number of inventive bristles in contact with the surface during painting as the inventive bristles are pliable or softer compared to prior art bristles even though each of this inventive bristles is larger in one cross-sectional dimension, i.e. a first dimension and the first thickness. This is accomplished by the elongated cross sectional shape of the inventive bristle being mixed in together with longer and/or shorter but not as thick other types of bristles, which bristle blend unexpectedly creates larger and/or more varied shapes of "voids" or space between bristles where paint is deposited or held or stored after and when the paint brush is dipped into paint as these "voids" or spaces or interspaces enables a lesser degree of compaction or packing of the blend of bristles due to an elongated or flattened or oval crosssectional shape of the inventive bristle maximising both the amount of paint that the paint brush is able to "hold" during painting and the amount of paint that the paint brush is able to release during the same painting work. The larger size in one cross-sectional dimension, i.e. the first thickness, of the inventive bristle in combination with it being in itself made up of a "blend" of at least two different thermoplastic polymers, i.e. Polybutylene terephthalate (PBT) or Polyethylene terephthalate (PET) or Polytrimethylene terephthalate (PTT) or Polypropylene (PP) or polyamide (PA ) or Polyvinylchloride (PVC) mixed with Thermoplastic polyester elastomer (TPE-E), means that the inventive bristle is able to be provided with a larger thickness than commonly done for prior art bristles as the softness/pliability of the inventive bristle is optimised so that this bristle is not too stiff if bent in a direction parallel or substantially parallel with its largest thickness or larger first dimension or thickness, i.e. in a direction parallel with the first axis,. This unexpected improvement of the paint brush comprising a plurality of inventive bristles blended with at least one other type of bristle having a corresponding cross-sectional thickness smaller than the first thickness of the inventive bristle in regard of pliability of the paint brush makes it unexpectedly docile, i.e. not too soft or stiff, for better ergonomics as it gives resistance but less rebound during painting. The inventive mix of at least two different bristles of which one type is the inventive bristle with a larger crosssectional dimension, i.e. the first thickness, than a corresponding cross-sectional dimension or thickness of the other type of bristle(s) means that when painting the dynamically changing shape or bending of the bristles in the bundle of bristles achieves an unexpected and more docile inventive paint brush compared to prior art ones while, at the same time, achieves both a maximised "uptake" of paint when dipping the paint brush in paint and release or discharge of paint from the paint brush during painting. The bristle is provided with a larger thickness in one direction in a cross-sectional plane without being too stiff in that same direction as the bristles has an optimised softness in that same direction.

The paint brush and synthetic bristle according to the invention accomplish longer and extended paint coverage during and after painting. The paint brush and bristle according to the invention accomplish a larger surface to be painted before having to re-dip the paint brush in paint during painting. The inventive paint brush and bristle accomplish performing longer paint strokes during painting before restarting a new painting stroke. The paint brush and bristle according to the invention enables a larger surface to be painted for each paint stroke before having to restart a new paint stroke and/or re-dip the paint brush in paint to "fill it up" anew. The inventive paint brush and bristle accomplish a larger surface to be painted for each paint stroke while reducing the effort to paint as the paint brush is provided with an optimised pliability/docility. The paint brush and synthetic bristle according to the invention provide a pliable but not too soft or stiff paint brush for better ergonomics as it gives an optimised resistance and rebound during painting.

In the context of the present invention under the term "bristle" or "monofilament" there is understood an elongated flexible body having a first end and a second end. The first end of the bristle or monofilament forms a free tip which usually contacts a surface to be coated with paint. The first end is part of the tip section of the monofilament or bristle. The second end is part of a root section where the bristle or monofilament is contained in and/or fastened in a bristle carrier. The free end of the inventive bristle is shaped with a straight cut-off tip or tipped or tapered into a narrowing tip or simply just provided with a blunt or more or less sharp tip.

In case of tipped or tapered or rounded bristles, the "thickness" throughout this application relates to the thickness of the root section of the bristles.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be explained in further details with reference to the drawings showing aspects thereof.

Figs, 1a-b show a paint brush having bristles of two or three different lengths or substantially the same length or the same length and two or three different thicknesses according to the invention.

Figs. 2a-c show the left part of the paint brush in Figs, 1a-b in cross-section having bristles of two or three different lengths and two or three different thicknesses according to the invention.

Fig. 3 shows in perspective a cross-section of a paint brush head of a paint brush along lines A-A in Figs, 1a-1b having two or three or more different types of bristles with two or three different lengths and wherein the first type of bristle according to the invention is thicker in a first dimension than the other type(s) of bristles(s).

Fig. 4 shows a free end of the first type of bristle with three differently shaped tips, one tip being cut-off straight in solid lines, another tip being rounded in dotted lines, and a third tip being rounded but with a sharper tip or smaller radius of the tip in dotted lines, according to the invention in more detail.

Figs. 5a-e show the first type of bristle in cross-section according to the invention in more detail with its larger first thickness in one direction in five different configurations compared to the other type(s) of bristle(s).

Figs. 6a-c show in planar views a bundle of bristles inside a bristle holder/carrier of the paint brush of Figs, 1a-b, 2a-c and 3 from one end, i.e. from below of the cross-sectional view in the direction of arrows B-B in Fig. 3, with its bristles of respectively two, three or more different types of bristles mixed in different configurations/patterns according to the invention.

DETAILED DESCRIPTION Aspects of the present disclosure will be described more fully hereinafter with reference to accompanying drawings. The tools and their parts disclosed herein can, however, be realized in many different forms and should not be construed as being limited to the aspects set forth herein. Like numbers in the drawings refer to like elements throughout.

The terminology used herein is for the purpose of describing particular aspects of the disclosure only, and is not intended to limit the disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

In the drawings and specification, there are disclosed exemplary aspects of the disclosure. Many variations and modifications can be made to these aspects without substantially departing from the principles of the present disclosure. Thus, the disclosure should be regarded as illustrative rather than restrictive, and not as being limited to the particular aspects discussed above. Accordingly, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, for example, definition of dimensions such as width or breadth or height or length or diameter depends on how exemplary aspects are depicted, hence, if depicted differently, a shown width or diameter in one depiction is a length or thickness in another depiction.

It should be noted that the word "comprising" does not necessarily exclude the presence of other elements or steps than those listed and the words "a" or "an" preceding an element do not exclude the presence of a plurality of such elements. It should further be noted that any reference signs do not limit the scope of the claims, that the example aspects may be implemented at least in part by means of both hardware and software, and that several "means", "units" or "devices" may be represented by the same item of hardware.

The different aspects of the invention disclosed herein can be combined with other aspects described herein, either can two aspects be combined or more than two aspects be combined.

The present invention as shown in Figs. 1 - 6c relates to a paint brush 1 and parts making it up according to the invention. The paint brush 1 comprises a handle 2, a bristle carrier 20 and a plurality of synthetic bristles or monofilaments, i.e. a bundle, mixture or blend 3 of bristles 10, 11, 12, comprising one, two, three or more types of bristles of which one or more of the bristles types has one or more dimensions being different or the same as the other bristles.

At least a first type of synthetic bristle 10 according to the invention has an oval cross sectional shape. By oval cross sectional shape is meant an elongated or flattened crosssectional shape, such as an egg shape, an ellipse shape, a broad or narrow ellipse shape, a rectangular shape having rounded corners, a cassini oval shape and the like. The oval cross sectional shape has a first axis, being an longitudinal axis, and a second axis perpendicular to the first axis or longitudinal axis.

The first axis or longitudinal axis defining and/or being coinciding with a first dimension and thickness W being the largest thickness of the synthetic bristle 10 and the second axis defining and/or being coinciding with a second dimension and thickness T being the largest thickness of the bristle 10 being perpendicular to the first axis.

The first and/or second axis may each correspond to an axis of symmetry of the oval cross sectional shape.

The first type of bristle 10 has in at least one dimension a thickness being larger than a corresponding thickness of any of the other types of bristles 11, 12. The first type of bristle 10 has at least a first thickness W in a first dimension being larger than its second thickness T in a second dimension, wherein first thickness W is perpendicular or substantially perpendicular to the second thickness T, see Figs. 2a-c, 3, 4, 5a-d, and 6a-c (Fig. 4 shows a free end 10a of bristle 10 enlarged and 5a-6c show its cross-section in four different configurations) and is an elongated moulded bristle made from a polymer material of at least two or exactly two different mouldable polymers 10', 10", preferably two different thermoplastic polymers (see Figs. 5a-5e). ). The polymer material making up bristle 10 is composed of a first polymer 10' being Polybutylene terephthalate (PBT) or Polyethylene terephthalate (PET) or Polytrimethylene terephthalate (PTT) or Polypropylene (PP) or polyamide (PA ) or Polyvinylchloride (PVC) and a second polymer 10" being a Thermoplastic polyester elastomer (TPE-E). One polymer mixture is Polybutylene terephthalate (PBT) and Thermoplastic polyester elastomer (TPE-E). Another polymer mixture is Polyethylene terephthalate (PET) and Thermoplastic polyester elastomer (TPE-E). Yet another polymer mixture is Polytrimethylene terephthalate (PTT) and Thermoplastic polyester elastomer (TPE-E).

Referring to Figs, la and lb, the bristle carrier 20 holds the plurality of synthetic bristles 10, 11, 12. The plurality of bristles 10, 11, 12 forms the bristle pack/bundle 3 or paint brush head 4 which is attached to the handle 2 and/or bristle carrier 20 by means of an adhesive 30 (shown in Figs. 2a-c, 3 and 6a-c) or any other suitable fastening means. The bristle carrier 20 may be a ferrule. Paint brush 1 is of a "T"-form with an essentially flat or plane configuration. The paint brush head 4 may be of cylindrical shape, e.g. a shape being symmetrically formed along/around its longitudinal axis. The handle 2 has its bristle carrier or ferrule 20 attached to one end of the handle 2. Paint brush handles 2, ferrules 20 and methods of securing a paint brush head 4 in a ferrule to make up a paint brush 1 are known in the art.

The synthetic bristles 10, 11, 12 are arranged tangent to each other along their length into the bundle 3 of bristles and have a first free end 10a, 11a, 12a forming a first bristle bundle end 13 and are aligned at a second/root bristle end 10b, 11b, 12b of the bristles into a second bundle end 15 of the bristle bundle 3 obtaining a flush or substantially flush bristle end surface or bundle end surface 14. The bristle carrier 20 extends between a first bristle carrier end 21 having a first bristle carrier end surface 22 and a second bristle carrier end 23. The first bristle carrier end surface 22 is aligned with the bundle end surface 14 and the bristle carrier 20 extends from the bundle end surface 14 along the length of the bristles 10, 11, 12 to at least partly surround the second bristle ends or root bristle ends 10b, 11b, 12b of the plurality of bristles 10, 11, 12 to form the second bundle end 15 for attachment of the paint brush head to the paint brush 1.

In general, the paint brush head 4 has a first and second end, the first or upper end of Figs, lab comprising the free ends 10a, 11a, 12a of the bristles 10, 11, 12 and the second or lower end of Figs, la-b comprising the root ends 10b, 11b, 12b of the synthetic bristles attached to the bristle carrier 20, wherein the second paint brush head end may have the bristle carrier end surface 22 flush with the second bristle bundle end 15 and their bristle end surfaces 14. The bristle carrier end surface 22 does not have to be flush with the bristle root ends 10a, 11a, 12a, the second bristle bundle end 15 and their bristle end surfaces 14, instead a cavity or recess 24, i.e. due to a distance between the bristle end surfaces 14 and the bristle carrier end surface 22 as measured in a direction along the length of the bristles 10, 11, 12, could be formed between the end surfaces 14 of the bristles and the bristle carrier end surface 22. The bristles 10, 11, 12 each have a free end 10a, 11a, 12a (see upper part of paint brush 1 in Figs. la-b, 2a-c, and 3, and the free end in more detail in Fig. 4) forming the first bundle end 13 that primarily contacts the surface to be painted during painting. Recess 24 in the bristle carrier 20 makes the bristle carrier hollow to provide a receiving cavity of all bristles 10, 11, 12 to enable encircling and enclosing them at their root ends 10b, 11b, 12b to hold them in place and to easily and more distinctly be able to position them inside the recess 24 before attaching at least the root ends 10b, 11b, 12b of the bristles therein and to each other at least partly, i.e. bristles in or closer to the middle of the bristle bundle 3 are only attached to each other while other bristles are attached both to each other and the inside of the bristle carrier 20 by means of the adhesive 30 forming a matrix around and between each and every bristle, at least partly. In some aspects, a sufficient length of the bristle root ends 10b, 11b, 12b is attached to the inside of the bristle carrier 20 and/or to other bristles 10, 11, 12, either by the adhesive or by a combination of adhesive 30 and fusion with the inner material of the bristle carrier 20.

The synthetic bristle 10 (see Figs. 4 showing its free end enlarged and 5a-6c showing its crosssection in at least four exemplary aspects) in one aspect is an elongated moulded bristle made from a suitable material of at least two or exactly two different mouldable polymers 10', 10", preferably two different thermoplastic polymers (see Figs. 5a-5e). In Figs. 5d and 5e, bristle 10 is composed of two different mouldable thermoplastic polymers, the first polymer 10' is Polybutylene terephthalate (PBT) or Polyethylene terephthalate (PET) or Polytrimethylene terephthalate (PTT) or Polypropylene (PP) or polyamide (PA) or Polyvinylchloride (PVC) and the second polymer 10" is a Thermoplastic polyester elastomer (TPE-E). The bristle 10 in another aspect is an elongated moulded bristle made from a suitable material being a mixture of at least two different mouldable polymers 10', 10", preferably two different thermoplastic polymers (see Fig. 5a-5c). In Figs. 5a-5c, the bristle 10 is composed of a solid phase mixture of at least two or exactly two different mouldable thermoplastic polymers, the first polymer 10' is Polybutylene terephthalate (PBT) or Polyethylene terephthalate (PET) or Polytrimethylene terephthalate (PTT) or Polypropylene (PP) or polyamide (PA) or Polyvinylchloride (PVC) and the second polymer 10" is a Thermoplastic polyester elastomer (TPE-E). The suitable material of the bristle 10 in Figs. 5a-5c is either a mixture of the two different mouldable thermoplastic polymers being Polybutylene terephthalate (PBT) or Polyethylene terephthalate (PET) or Polytrimethylene terephthalate (PTT) or Polypropylene (PP) or polyamide (PA) or Polyvinylchloride (PVC) and a Thermoplastic polyester elastomer (TPE-E) or, as shown in Figs. 5d and 5e, the bristles 10 is made of two separate entities or halves 10' and 10" joined together. Here, a first half 10' is made of Polybutylene terephthalate (PBT) or Polyethylene terephthalate (PET) or Polytrimethylene terephthalate (PTT) or Polypropylene (PP) or polyamide (PA) or Polyvinylchloride (PVC) and a second half 10" is made of a Thermoplastic polyester elastomer (TPE-E). The halves 10' and 10" do not necessarily have to be halves, they could instead be quarters or even smaller, such as sixth or eighth parts. Here, the halves 10', 10" of Fig. 5d and 5e is joined together horisontally in Fig. 5d and vertically in Fig. 5e in the centre of the bristle 10 by adhesion or fusion or by melting them together longitudinally. The first thickness W and second thickness T of the bristle 10 is shown in Figs. 5a-5e, and also the positioning of the joint in bristle 10 is defined by a third thickness t in Fig. 5d and a fourth thickness w in Fig. 5e corresponding to the same measures or directions as W and T. These thicknesses t and w is shown to define the orientation and position of the joint between the two separate but joined or integrated entities 10' and 10" of bristle 10. Here, t is larger than zero but smaller than T and is between 25% (T/4) and 75% of T (3T/4); between 30% and 60% of T, or between 40% and 55% of T. The same goes for w, i.e. w is larger than zero but smaller than W, and is between 25% (W/4) and 75% of W (3W/4); between 30% and 60% of W, or between 40% and 55% of W. In other aspects, the first thickness W of the synthetic bristle 10 is at least about 30% larger than the second thickness T or is between about 35% to 300% larger than the second thickness T, or between about 40% to 200% larger than the second thickness T . The second thickness T corresponds to a first diameter D1 (see tables below) and the first thickness W corresponds to a second diameter D2 (see tables below) when the cross-section of the bristle 10 is oval. In some other aspects, T is between 0.1 to 0.25 mm and W is between 0.3 to 0.5 mm, or T is between 0.15 to 0.23 mm and W is between 0.35 to 0.45 mm; or T is between about 0.2 to 0.21 mm and W is between about 0.36 to 0.4 mm, or T is about 0.18 to 0.21 mm and W is about 0.36 to 0.39 mm. In another aspect, T is about 0.19 to 0.21 mm and W is between about 0.37 to 0.388 mm. Alternatively, the former intervals are broader or even narrower.

Configuration, shape, and cross-section of the synthetic bristle 10 according to the invention are seen in detail in Figs. 4 and 5a-5e. The outer periphery and cross-section of the bristle 10 has a primary cross-sectional dimension in at least one first thickness W being larger than in at least one second dimension of at least one second thickness T measured perpendicular to the direction of the at least one first thickness W of the primary cross-sectional dimension. The outer periphery of the bristle 10 has a primary cross-sectional dimension that makes the crosssection of the bristle 10 substantially oval or oval, substantially elongated or elongated or into any other suitable shape being larger in one cross-sectional dimension, such as the first thickness W, this shape may be at least partly symmetrical or asymmetrical, but is preferably symmetrical. The cross-section of the bristle 10 is provided with a substantially rounded shape in Figs. 5a-d or with a less rounded shape, e.g. a substantially square or square shape, a substantially five-edged or five-edged shape, a substantially hexagonal or hexagonal shape, a substantially seven-edged shape or seven-edged shape, a substantially octagonal shape or octagonal shape, a substantially nonagonal shape or nonagonal shape, or a combination of any of these shapes, e.g. with a smooth rounded surface over half its periphery while the other half of its periphery comprises one or more corners or edges (not shown) as long as the bristle 10 is larger in one cross-sectional dimension, such as the first thickness W.

The synthetic bristle 10 (Fig. 4 shows its free end 10a enlarged and Figs. 5a-6c show its crosssection in exemplary aspects) is provided with a sharp-cut free end with at least two corners shown in solid lines or preferably provided with at least a partially rounded free end 10a as shown in dashed lines of two differently rounded contours or outlines in Fig. 4. Alternatively the free end may be tapered or tipped or flagged into any other suitable shape.

Referring to Fig. 3, an aspect of a paint brush head 4 for a paint brush (shown in Figs la-b) is illustrated comprising the bristle carrier 20 and the plurality of synthetic bristles 10, 11, 12 being grouped into the bristle bundle 3 and attached to the bristle carrier 20. The first bundle end 13 is aligned to the flush or substantially flush bundle end surface 14 before being attached to the bristle carrier 20.

The shape of the bristle carrier recess 24 corresponds to the cross-sectional shape of the second bundle end 15 of the bundle 3 of bristles 10, 11, 12. The outer shape of the bristle carrier 20 and its inner recess 24 could be shaped in many different ways opening up for a large design freedom when designing a paint brush 1.

The bundle 3 of synthetic bristles 10, 11, 12 may be attached to the bristle carrier 20 by means of the adhesive 30 applied within the recess 24, e.g. at least on side surfaces of the recess 24, if the recess is a through hole, and optionally also on a bottom surface of the recess 24 if the recess is a bottom hole. According to an aspect, the bundle 3 of bristles 10, 11, 12 is attached to the bristle carrier 20 by means of fusion by applying heat.

The synthetic bristle 10 is made of at least two different polymers, preferably thermoplastic polymers. In one aspect, the synthetic bristle 10 is made of at least two different polymers, preferably thermoplastic polymers, in continuous solid phase made by at least Polybutylene terephthalate (PBT) or Polyethylene terephthalate (PET) or Polytrimethylene terephthalate (PTT) or Polypropylene (PP) or polyamide (PA) or Polyvinylchloride (PVC) and Thermoplastic polyester elastomer (TPE-E) and is configured at least partially with a cross sectional shape having a larger or largest thickness, such as the first thickness W, in one direction in a crosssectional plane. In another aspect, the synthetic bristle 10 is made of at least a mixture of at least Polybutylene terephthalate (PBT) or Polyethylene terephthalate (PET) or Polytrimethylene terephthalate (PTT) or Polypropylene (PP) or polyamide (PA) or Polyvinylchloride (PVC) and a Thermoplastic polyester elastomer (TPE-E) and is configured at least partially with a cross sectional shape having a larger or largest thickness, such as the first thickness W, in one direction in a cross-sectional plane. In yet another aspect, the synthetic bristle 10 is made of at least a mixture of at least Polybutylene terephthalate (PBT) or Polyethylene terephthalate (PET) or Polytrimethylene terephthalate (PTT) or Polypropylene (PP) or polyamide (PA) or Polyvinylchloride (PVC), and a Thermoplastic polyester elastomer (TPE-E) in a ratio of between about 51 - 99% of PP (percentage by weight, wt%) and between about 1 -49% of TPE-E (percentage by weight, wt%) and is configured at least partially with a cross sectional shape having a larger or largest thickness, such as the first thickness W, in one direction in a cross-sectional plane.

In another aspect, the synthetic bristle 10 is made of a mixture of only Polybutylene terephthalate (PBT) or Polyethylene terephthalate (PET) or Polytrimethylene terephthalate (PTT) or Polypropylene (PP) or polyamide (PA) or Polyvinylchloride (PVC) and a Thermoplastic polyester elastomer (TPE-E) in a ratio of between about 60 - 99% PBT or PET or PTT or PP or PA or PVC (percentage by weight, wt%) and between about 1 - 40% TPE-E (percentage by weight, wt%), and is configured at least partially with a cross sectional shape having a larger or largest thickness, such as the first thickness W, in one direction in a cross-sectional plane so that the cross-section of the bristle 10 is elongated and/or oval making the bristle more pliable in a direction in the cross-sectional plane across or perpendicular to its larger or largest first thickness W. In an additional aspect, the synthetic bristle 10 is made of a mixture of only Polybutylene terephthalate (PBT) or Polyethylene terephthalate (PET) or Polytrimethylene terephthalate (PTT) or Polypropylene (PP) or polyamide (PA) or Polyvinylchloride (PVC), and a Thermoplastic polyester elastomer (TPE-E) in a ratio of between about 70 - 99% PBT or PET or PTT or PP or PA or PVC (percentage by weight, wt%) and between about 1 - 30% TPE-E (percentage by weight, wt%), and is configured at least partially with a cross sectional shape that has a larger or largest first thickness W in one direction in a cross-sectional plane/ dimension, whereby the ratio between PBT or PET or PTT or PP or PA or PVC and TPE-E is chosen so that even if the cross-section of the bristles 10 is elongated and/or oval the bristle has a stiffness or pliability being almost the same or closely to or about the same or exactly the same when bent in any direction, such as in the same direction/dimension in a crosssectional plane as its larger or largest first thickness W or when bent in a direction in a crosssectional plane inclined in relation to its larger or largest first thickness W or when bent in a direction in a cross-sectional plane perpendicular or across its larger or largest first thickness W (i.e. when bent in a direction in a cross-sectional plane being parallel with its smaller second thickness T) or when bent in dynamically changing or varying directions in a cross-sectional plane relative to its larger or largest first thickness W, such as during painting (see Figs. 3, 4, 5a-5e, and 6a-6c). A ratio between the first thickness W and the second thickness T may be the double, i.e. W is about two times T (W = 2T), or in some aspects larger. The first thickness W is perpendicular to the smaller second thickness T, i.e. W extends in a direction in a crosssectional plane being 90<°>in relation to T.

In some aspects, the synthetic bristle 10 is made of at least between about 70 - 95% PP or PBT or PET or PTT or PA or PVC and between about 5 - 30% TPE-E; or made of at least between about 75 - 91% PBT or PET or PTT or PP or PA or PVC and between about 9 - 25% TPE-E; or made of at least between about 80 - 95% PBT or PET or PTT or PP or PA or PVC and between about 5 - 20% TPE-E; or made of at least between about 85 - 95% PBT or PET or PTT or PP or PA or PVC and between about 5 - 15% TPE-E. One polymer mixture is made of at least about or more than 90% PBT or PET or PTT or PP or PA or PVC and about or less than 10% TPE-E as its softening effect in some aspects decreased or diminished at higher concentrations. Another polymer mixture is made of about 90% PBT or PET or PTT or PP or PA or PVC and about 10% TPE-E as its softening effect in some aspects then is optimised. Above and below percentages, i.e. = % regarding the ratios of mixing polymer materials and amounts of material in relation to each other is measured in percentage by weight, i.e. wt%. The percentages defined in relation to sizes and the first thickness W being larger than the second thickness T specify sizes/dimensions in relation to each other, such as length, width and depth, and not the quantities or amounts of materials mixed together.

In some aspects, the synthetic bristle 10, besides also being made by any of the above defined thermoplastic polymers 10', 10" in any associated ratio or shape/configuration, is configured with an at least in part substantially oval or substantially oval or exactly oval cross sectional shape as shown in Figs. 4 and 5a-5e, i.e. oval cross sectional shape.

In one aspect, the synthetic bristle 10 has an outer periphery or outer surface comprising an at least partially rough or rugged or ragged or uneven or irregular or bumpy or knurled or cut or pierced or teared or knocked or weared or knotty or hollow or burrowed surface 16. In one other aspect, the synthetic bristle 10 is configured with the at least partially rough or rugged or ragged or uneven or irregular or bumpy or knurled or cut or pierced or teared or knocked or weared or knotty or hollow or burrowed outer surface 16 over at least half its outer surface. In still another aspect, the synthetic bristle 10 is configured with the at least partially rough or rugged or ragged or uneven or irregular or bumpy or knurled or cut or pierced or teared or knocked or weared or knotty or hollow or burrowed outer surface 16 over not more than half its outer surface. In a further aspect, the synthetic bristle 10 is configured with the at least partially uneven outer surface 16 on/over substantially half its outer surface or on/over about/approximately half its outer surface or on/over closely to half its outer surface. The synthetic bristle 10 according to another aspect has an at least partially uneven outer surface 16 provided with at least one or a plurality of dents and/or craters and/or holes and/or open cells 17. The dents and/or craters 17 may form a gear shape as shown in Figs. 5b and 5c. If only one dent/crater 17 is provided on the surface of the bristle 10, this dent/crater 17 is large. If more than one dent/crater or a plurality of dents or craters 17 are present on the outer surface, these dents or craters are smaller compared to only having one dent or crater. The dents 17 are in one aspect of substantially the same or the same size while in another aspect of different sizes. The dents 17 are in one aspect of substantially the same shape or the same shape while in another aspect of different shapes. The dents 17 are in one aspect of substantially the same size and/or shape or the same size or shape while in another aspect of different sizes and/or shapes. The dents 17 are in one aspect in combination with any of the above aspects symmetrically arranged on the outer surface of the bristle 10 while in another aspect in combination with any of above aspects asymmetrically or unsymmetrically arranged on the outer surface of the bristles 10. Some or several of the dents 17 are in one aspect in combination with any of the above aspects symmetrically arranged on the outer surface of the bristle 10 while some or several of the other dents 17 are asymmetrically or unsymmetrically arranged on the outer surface of the bristle 10. These dents 17 are in some aspects provided with the same depth and/or radius (if having rounded shapes) but in other cases provided with differing depths and/or radii. One or more or some or several dents 17 are in other aspects provided with the same depth and/or radius (if having rounded shapes) while one or more or some or several other dents 17 are provided with differing depths and/or radii.

According to an aspect, the paint brush 1 comprising the handle 2 having at one end the bristle carrier 20 and the bundle 3 of synthetic bristles fastened in the bristle carrier 20 comprises at least a plurality of synthetic bristles 10 according to any of the preceding and below aspects of polymer materials and shape and/or surface configurations.

The invention provides a synthetic bristle 10 for mixing or blending into a bundle 3 with at least one other type of synthetic and/or natural bristles 11, 12 for a paint brush 1, such that the paint brush 1 is provided with a tuft or paint brush head 4 having an optimised number of bristles, types of bristles and orientation and positioning of bristles in relation to each other when mixed/blended and attached together in the bundle 3 whereby the paint brush achieves an optimal painting ability due to an increased paint holding minimizing the need of re-dipping the paint brush when too little amount of paint is released during painting at the end of a painting stroke and paint delivery ability maximising the paint released onto the surface during painting. This increases the painting time for each painting stroke and minimizes the number of times the paint brush 1 must be dipped with new/more paint. This optimises the area of effective painting surface of the paint brush by optimising the number of the first type of bristles 10 in contact with the surface during painting being more pliable or softer compared to prior art bristles even though each bristle 10 is larger in one cross-sectional dimension or thickness, i.e. the larger or largest first thickness W. This is accomplished by the elongated cross sectional shape of the first type of bristle 10 being mixed in together with longer and/or shorter but not as thick types of bristles 11, 12 unexpectedly creating larger and/or more varied shapes of "voids" or spaces between bristles where paint is deposited or held or stored after and when the paint brush 1 is dipped into paint as these "voids" or spaces or interspaces enables a lesser degree of compaction or packing of the blend of bristles 10, 11, 12 due to the elongated shape of the first type of bristle 10 maximising both the amount of paint that the paint brush 1 is able to "hold" during painting and the amount of paint that the paint brush 1 is able to release during the same painting. The elongated shape of the first type of bristle 10 in combination with it being made up of the "blend" of at least two different thermoplastic polymers, i.e. Polybutylene terephthalate (PBT) or Polyethylene terephthalate (PET) or Polytrimethylene terephthalate (PTT) or Polypropylene (PP) or polyamide (PA) or Polyvinylchloride (PVC) and Thermoplastic polyester elastomer (TPE-E), also means that the first type of bristle 10 is able to be provided with a larger thickness than commonly done for prior art bristles as the softness and/or pliability of the bristle 10 is optimised so that the bristle 10 is not too stiff if bent in the same direction in cross-sectional plane as its larger or largest first thickness W. This is an unexpected improvement of the paint brush 1 comprising a plurality of the first type of bristle 10 blended with at least one other type of bristle 11, 12 having at least one largest thickness or corresponding cross-sectional dimension smaller than the first type of bristle 10 in regard of the pliability of the paint brush 1 making it unexpectedly docile, i.e. not too soft or stiff, for better ergonomics as it gives resistance but less rebound during painting. This mix of at least two different bristles of which one type is the first type of bristle 10 with a larger cross-sectional dimension, i.e. first thickness W, than the other type of bristle(s) 11, 12 means that when painting the dynamically changing shape or bending of bristles 10, and 11 and/or 12 in the bristle bundle 3 achieves an unexpected and more docile paint brush 1 compared to prior art ones while, at the same time, achieves both a maximised "uptake" of paint when dipping the paint brush in paint and release or discharge of paint from the paint brush 1 during painting.

This paint brush 1 and its synthetic bristles 10 accomplish longer and extended paint coverage during and after painting. The paint brush 1 and its bristles 10 accomplish a larger surface to be painted before having to re-dip the paint brush 1 in paint. This paint brush 1 and its bristles 10 accomplish longer paint strokes to be performed during painting before restarting a new painting stroke. The paint brush 1 and its bristles 10 enables a larger surface to be painted for each paint stroke before having to restart a new paint stroke and/or re-dip paint brush 1 in paint to "fill it up". This paint brush 1 with bristles 10 accomplish a larger surface to be painted for each paint stroke while reducing the effort to paint as the paint brush is optimally pliable and/or docile. This paint brush 1 with bristles 10 give a pliable but not too soft or stiff paint brush for better ergonomics as it gives an optimised resistance and rebound during painting.

Test results of bundles 3 with a first variant of synthetic bristles 10 made of 100% PBT only (no TPE-E) is shown in Tables la (synthetic bristle length = 64 mm) and lb (synthetic bristle length = 71 mm) below. Test results of bundles 3 with a second variant of the bristle 10 made of 10% TPE-E and 90% PBT and a third variant of the bristle 10 made of 20% TPE-E and 80% PBT re shown pairwise in Tables 2a (synthetic bristle length = 64 mm) and 3a (synthetic bristle length = 71 mm), and 2b (synthetic bristle length = 64 mm) and 3b (synthetic bristle length = 71 mm), respectively, below. Above/Below percentages of mixed amounts of material is measured in percentage by weight (wt%), and not percentage by volume.

Table la (OVAL GEAR SHAPE 0.30 X 64 MM BT101 (100% PBT)) Image available on "Original document" Table lb (OVAL GEAR SHAPE 0.30X 71 MM BT101 (100% PBT)) Image available on "Original document" Table 2a (OVAL GEAR SHAPE 0.30 X 64mm Bristle 101 (90% PBT and 10% TPE-E)) Image available on "Original document" Table 2b (OVAL GEAR SHAPE 0.30 X 64mm Bristle 101 (80% PBTand 20% TPE-E)) Image available on "Original document" Table 3a (OVAL GEAR SHAPE 0.30 X 70mm Bristle 101 (90% PBTand 10% TPE-E)) Image available on "Original document" Table 3b (OVAL GEAR SHAPE 0.30 X 70mm Bristle 101 (80% PBTand 20% TPE-E)) Image available on "Original document"

Claims (10)

1. A synthetic bristle (10) for a paint brush (1), which synthetic bristle (10) is made of at least two different polymers made by a mixture of at least Polybutylene terephthalate (PBT) or Polyethylene terephthalate (PET) or Polytrimethylene terephthalate (PTT) or Polypropylene (PP) or polyamide (PA) or Polyvinylchloride (PVC) and a Thermoplastic polyester elastomer (TPE-E) in a ratio of between about 70 - 99% (percentage by weight, wt%) PBT or PET or PTT or PP or PA or PVC and between about 1 - 30% (percentage by weight, wt%) TPE-E, and which synthetic bristle (10) has an at least in part substantially oval cross sectional shape comprising a thickness (W) in a first dimension that is larger than a thickness (T) in a second dimension being substantially perpendicular or perpendicular to the first dimension and thickness, wherein the synthetic bristle (10) comprises an at least partially uneven, such as rough or rugged or ragged or irregular or bumpy or knurled or cut or pierced or teared or knocked or weared or knotty or hollow or burrowed, outer surface (16) and wherein the synthetic bristle (10) is configured with the at least partially uneven outer surface (16) over at least half its outer surface or not more than half its outer surface.

2. A synthetic bristle (10) according to claim 1, wherein the synthetic bristle (10) is made of at least between about 75 - 91% PBT or PET or PTT or PP or PA or PVC and between about 9 - 25% TPE-E.

3. A synthetic bristle (10) according to claim 1 or 2, wherein the synthetic bristle (10) is made of at least between about 80 - 90% PBT or PET or PTT or PP or PA or PVC and between about 10 - 20% TPE-E.

4. A synthetic bristle (10) according to any preceding claim, wherein the synthetic bristle (10) is made of more than about 85% PBT or PET or PTT or PP or PA or PVC and less than about 15% TPE-E.

5. A synthetic bristle (10) according to any preceding claim, wherein the synthetic bristle (10) is made of about 90% PBT or PET or PTT or PP or PA or PVC and about 10% TPE-E.

6. A synthetic bristle (10) according to any preceding claim, wherein the synthetic bristle (10) is configured with an oval cross sectional shape.

7. A synthetic bristle (10) according to any of the preceding claim, wherein the synthetic bristle (10) is configured with the at least partially uneven outer surface (16) on substantially half its outer surface or on approximately half its outer surface or on half its outer surface.

8. A synthetic bristle (10) according to any of thepreceding claim, wherein the at least partially uneven outer surface (16) of the synthetic bristle (10) is provided with at least one or a plurality of dents and/or craters and/or holes and/or open cells (17).

9. A synthetic bristle (10) according to any preceding claim, wherein the first thickness (W) of the synthetic bristle (10) is at least about 1.3 times larger than the second thickness (T) or is between about 1.35 to three times larger than the second thickness (T), or between about 1.4 to two times larger than the second thickness (T).

10. A paint brush (1) comprising a handle (2) having at one end a bristle carrier (20) and a bundle (3) of bristles fastened in the bristle carrier (20), which bristle bundle (3) comprises at least a plurality of synthetic bristles (10) according to any of the preceding claims.