CN1241122A - Improvement in brush making - Google Patents

Abstract

The present invention relates to a process for forming a two-component elastically bendable joint in a personal cleansing implement by injecting an elastomer into a void in a plastic handle or head at a temperature of at least 245°C, thereby enabling The elastomer is fused into the plastic to form an elastically bendable joint. The present invention also relates to a personal cleansing implement comprising an elastically bendable joint between a plastic material having a Vicat softening point below 245° C. and an elastomer, the elastomer being fused into the plastic material so that the elastomer does not separate from the plastic stretched to 120% of its unstressed length. The invention improves the bond and service life between elastomers and plastics.

Description

The improvement that brush is made

Invention field

The present invention relates to a kind of manufacture method of making personal cleanliness's instrument, particularly toothbrush bi-component, injection-molded.The invention particularly relates between a kind of improvement thermoplastic body and the thermoplastic elastomer and bond, make the bending that to bear repetition that flexibly connects between the material of instrument neck or head, and can not damage the bonding of junction.The invention still further relates to injection-molded, the bi-component personal cleanliness's instrument that between two component parts, have the high level bonding.

Background of invention

The profile of people's tooth requires the desirable bristle profile of toothbrush to cave in order to scrub oral cavity or outside surfaces of teeth, and in order to scrub tongue or tooth inner surface, it is protruding requiring desirable bristle profile.Yet that most of brushes remain is quite firm, one-piece construction and fixed in shape.The body of toothbrush and similar instrument is generally made by polypropylene or similar thermoplastic material.

In many brushes, second elastic component of employing such as thermoplastic elastomer is to help grasping or to form different outward appearances in handle.The bi-component brush adopts usually now and makes such as the injection molding process described in " the full-automatic double-color mold of Zahoransky " (Brossa publishing house, 1989).Manufacturing process generally includes the first molded step that employing can be held elastomeric vacancy, make the thermoplastic body.In second step, elastomer is expelled in the vacancy, in cooling with when solidifying, the elastomer in the vacancy is understood local mechanical usually and is fixed, and also is fused in the thermoplastic body.In handle, the connection request between thermoplastic body and the elastomer is generally not high.

But, some brushes are disclosed, they adopt a kind of connection, so that head can be with respect to curved handle, for example at EP-A-371,293 or EP-A-613, described in 636.In the described brush of these patents, flexibly connect the employing elastomer, helping or to improve flexiblely, being connected between elastomer and the body can be born bigger stress.

WO92/17092, WO92/17093 and WO96/02165 disclose has that elasticity is flexible, the toothbrush of head of supporting bristle, and head in certain embodiments is the form of two sections or multistage, but they link to each other to elastic bending each other.Elastomer is inserted in space between each segmentation whole or in part.In the brush of this structure, the bonding between elastomer and the body can be born the big stress that repeats to apply in frequent the use.But, all do not have in the above-mentioned file to describe and how between these two kinds of materials, to realize standing reusable solid connection.

Find surprisingly that at present the elastomer injection temperature is brought up on 190 ℃ of-210 ℃ of scopes of common employing, the fusion intensity between elastomer and the brush body can access sizable improvement, and does not make the elastomer heat damage.

Therefore, an object of the present invention is to provide a kind of technology of making personal cleanliness's instrument of injection-molded, bi-component, this instrument can be flexibly crooked, and durable in use.

Another object of the present invention provides a kind of personal cleanliness's instrument of injection-molded, bi-component, and the fusion intensity between its plastic body and the elastomer has had raising.

Brief summary of the invention

According to an aspect of the present invention, but provide a kind of technology that forms the connection of elastic bending at the handle or the head of personal cleanliness's instrument, this instrument comprises that one has the handle at both ends and at the head of handle one end, this head comprises a cleaning device, and this technology comprises following step:

I) provide an instrument blank, which comprises at least a plastic material zone that in head or handle, limits a vacancy space; And

Ii) under at least 245 ℃ temperature, elastomer is expelled in the vacancy space, thus elastomer is fused in the plastic material, but the junction surface of formation elastic bending.

According to a second aspect of the invention, provide a kind of and have elongate handle and at personal cleanliness's instrument of the head of handle one end, this head comprises a cleaning device; This handle or head be included in one by Vicat (dimension card) but softening point is lower than first area that 245 ℃ plastic material makes and the second area made by elastomer between the elastic bending junction surface, wherein, elastomer is fused in the plastic material, make the elasticity physical efficiency with the unseparated situation of plastic material under be stretched to 120% of its length that do not stress.

Technology of the present invention improvement between elastomer and plastics two components is provided bonding, make two components can bear repeated flex better, and can not weaken bonding by the flexible junction surface that fusion bonds together.Improved the durability of instrument thus.

Detailed description of the invention

Personal cleanliness's instrument of the present invention can be to have enough elongated handle and any instrument that is arranged on head handle one end, that have cleaning device and so on for user's grasping.This instrument can be for example toothbrush, hair brush or massage instrument.Especially a kind of toothbrush.

Head comprises cleaning device.Cleaning device can be the form of bristle, combing tooth, polishing material, rubber massaging pad and so on.In the preferred embodiment of this paper, instrument is a toothbrush, and cleaning device wherein comprises many bristles that stretch out from the head.

Head removably is connected in handle, so as for example when bristle with replaceable head after old, in this case, head has the position that connects handle.Head comprises many connected segmentations.The first head segmentation links to each other with handle.In a preferred embodiment, the handle and the first head segmentation are single-pieces by injection-molded formation.Preferably, handle and all head segmentations form by injection-molded in single mould.Under any circumstance, handle has the longitudinal axis that extends between its two ends.This axis also defines and the common head longitudinal axis that extends of handle axis.Preferably, head is the flat substantially structure with a pair of facing surfaces, head also have one with longitudinal axis vertical, with the substantially parallel lateral shaft of facing surfaces.Laterally mentioned herein or vertically refer to the direction that is parallel to horizontal and vertical axle respectively, unless refer else.

Comprise the joint of elastic bending in handle or head but instrument of the present invention and the essential characteristic that forms the technology of instrument are instrument or the instrument that forms thus, this joint comprises plastic material and elastomer.Refer to one at this " but joint of elastic bending " and comprise plastic material and elastomeric zone, this zone can be articulated and connected under the effect of a power suffered under the instrument regular service conditions, in addition, when this power was removed, instrument will be in 60 seconds, be preferably the same profile when getting back to beginning basically in 30 seconds.Preferably, but head comprises a kind of like this joint of elastic bending.

Head and total the making of handle by relative incompressible material, be preferably these materials and have elastic modelling quantity at least about 500MPa, be more preferably and have the elastic modelling quantity at least about 1000MPa, these materials are used always in the toothbrush manufacturing, especially plastic material.Particularly plastic material has and is lower than 245 ℃, is more preferably and is lower than 220 ℃, especially is lower than 200 ℃ Vicat softening point.The plastic material that is suitable for comprises for example polyamide and polypropylene.Polypropylene is preferably.The polypropylene that is suitable for comprises ' the polypropylene PM1600 ' (being sold by Shell) and from the Apryl 3400MA1 of Elf Atochem with 1500MPa elastic modelling quantity (ISO178).Preferably, such as from the blowing agent of the Hydrocerol HP20DP of Boehringer-Mannheim by polyacrylic weight content for from 1% to 3% preferably from 1.5% to 2.5% mixing mutually approximately approximately with polypropylene.In molded process, blowing agent helps polyacrylic flowing, and particularly guarantees used hinged can being formed uniformly.Handle itself is rigidity basically, and its shape is common during toothbrush is made.Handle also can select to comprise a neck, for example by comprising above-mentioned flexible bonding part, and makes its pliability stronger than the other parts of handle.

In the first step of technology of the present invention, an instrument blank is provided, this blank comprises that at least one limits the plastic material zone in a vacancy space in head or handle.Instrument blank elastomer is basically injected instrument before and also can be selected such as the instrument before other processing technologys such as installation cleaning device.At least one zone of plastic material can be the whole of instrument blank, also can be its less part.The plastic material that is suitable for as mentioned above.The vacancy space can be simple groove or the complicated shape in the head.It should be a multidimensional, so that head or handle weaken at this position or be flexible.In the preferred embodiment of this paper, the tool blank material package is drawn together and one or more head is divided into the groove of several segmentations or the vacancy space in space.Be preferably two, three or four segmentations, best is four segmentations.Increase the complexity of making than this more segmentation meeting, and in the toothbrush of a bristle pieces insert head segment section, this can be difficult to reach enough close pieces density in all segmentations of head.All head segmentations have any suitable spatial relationship each other, arrange such as being multilayer or for example being many quadrants in brush head.Preferably, all segmentations along head vertically order arrange, make from the head handle end sign in the free-ended vertical line of head and pass the first head segmentation, pass the second head segmentation then, the rest may be inferred.Especially, first a head segmentation that links to each other with handle and one or more other longitudinally towards the tactic head segmentation of head free end is arranged.In addition preferably, these segmentations all are individual layers so that any perpendicular to head two relatively the surface, pass head and the line that draws only passes a kind of material basically.Generally speaking, each head segmentation all is to make with identical materials, and these materials are preferably identical with handle, and they can both be made in single injection-molded step.

In the instrument of finishing, all head segmentations are connected means and link together.But as long as have at least an elastomer to be fused to the elastic bending joint of plastic areas, the connection means just can adopt any form with instrument of estimating function that is applicable to.The connection means can be for example adhesive, with plastics attachment, metal connector head segmentation one or that removably be connected in the head segmentation or be fused to elastomer in the plastics segmentation.In the preferred embodiment of this paper, at least one segmentation is connected in adjacent sectional or handle by being lower than the connection means that the elastomer of 500MPa constitutes by a kind of elastic modelling quantity basically.Here the meaning that " is made of a kind of elastomer basically " is meant that elastomer is the unique mechanical connection thing between a segmentation and adjacent sectional or the handle.Unique mechanical connection thing does not refer to not the continuous non-resilient attachment that connects all segmentations such as bridge joint or spring.But elastomer can have other material that is dispersed in wherein, such as the metal particle or the pigment that can be used to for example provide distinguished outward appearance.These additional materials can be ignored for the mechanical connection between all segmentations and/or the handle, and like this, removing not of they can have in essence change to bonding strength.In preferred embodiment, one or more segmentations that do not connect were arranged before the elastomer injection, the tool blank material package is drawn together several segmentations that do not connect, and these segmentations are only by preparing and providing the mould of instrument blank to remain on the position respect to one another.Space between all segmentations is the vacancy space, if filled out by elastomer, but these vacancy spaces have constituted the joint of elastic bending, so that a segmentation is hinged with respect to another segmentation.

In the splendid embodiment of this paper, head has an end face and a bottom surface, and the connection means are constituted from the elastomeric strip that end face extends to the bottom surface by traversing across head.For example, comprise along in the head of vertically tactic four segmentations of head, wherein first segmentation and the common extension of handle that one three such connection means are arranged.Elastomeric strip from one to next bar or can be different at the width of bar or the thickness on the length.More suitable is, the thickness that their axle is longitudinally measured is in about 0.1 millimeter to 10 millimeters scope, is preferably approximately from 0.3 millimeter to 5 millimeters, is more preferably approximately from 0.5 millimeter to 3 millimeters.

In other embodiments, segmentation links to each other by the hinge with the same material of segmentation in addition, and these hinges are thinner or narrow than the segmentation that they connected, and makes the entire tool blank form one interconnected whole.Certainly, in same instrument, can there be some to comprise the means that are connected of hinge and the other parts that substantially constitute by elastomer.Be called groove by the vacancy between hinged segmentation and the segmentation at this.The width of groove and the degree of depth are variable, and the distance between groove also is variable.Like this, can be different along the head deflection degree on head length and/or the width.It is transformable preferably having only transverse groove in this respect.But the position and the thickness of the hinge of all segmentations of change control connection of groove depth.In preferable hinged embodiment, head has a pair of facing surfaces, and some paired grooves are arranged on each face respect to one another, and making has a residual hinge between the two sides.Between about 4 to 6 millimeters, generally be about 5 millimeters toothbrush head, suitable groove depth is about 1.4 to 3 millimeters scope, preferably in about 1.5 to 2.8 millimeters scope for thickness.The thick scope about 0.4 to 2.0 millimeter of the groove that is suitable for is preferably in about 0.5 to 1.5 millimeter scope.Use transverse groove then, it is desirable to, the flexibility ratio of the hinge of close handle is low away from handle.Make head reach more uniform bending like this.It is variable to reach deflection degree, as long as change hinge thickness.In a preferred embodiment, the thickness of the hinge of close handle is to leave about 3 times of handle hinge farthest, preferably reaches about 2 times.One group of exemplary toothbrush hinge thickness with three transverse grooves begins to be about respectively 1.2,0.6 and 0.6 millimeters from handle end.If use identical hinge, will make the bending of head appear at the hinge at the most close handle place at first so along brush head.The degree of depth of the groove on the one side can be different from another opposite face.

The conference that adds of groove width increases gap between all segmentations, and has therefore strengthened the width of hinge, and this has increased the deflection degree of hinge.But, owing to preferably the cleaning device such as bristle is bearing in the segmentation, rather than be bearing on the elastomer of injecting between the segmentation, so the groove width that strengthens also will leave less space for cleaning device in given head dimensions.The groove width that is suitable for is preferably in about 1.2 to 2.0 millimeters scope in about 0.3 to 3.0 millimeter scope.Groove is preferably promptly slightly gradually little towards the bottom of groove inwardly, and appropriate is to assemble with about 3 to 10 ° angle, so that molded.Because tool flexion, groove width are also changing, the variation at groove top is bigger than trench bottom, and changing relatively is the function of the groove width and the degree of depth.Because this variation of groove width causes elastomeric compression or tractive in the groove, this shows that for given elastomer, the geometry of groove can be used to the bending of control tool.

Hinge can be the total length of groove, or is preferably, and has one or more gaps in hinge or to the side of hinge, and the groove in these zones is the complete dark of head.So just has the advantage of when molded head, having only an injection point for elastomer.The gap allows elastomer to flow to another side from a face in molding process.In a preferred embodiment, hinge is discontinuous, has two or more hinges, preferably is exactly that two hinges are connected to a segmentation its adjacent or are connected to handle.In this embodiment, between all hinges, plurality of gaps is arranged to each side.In straight-line groove, hinge width is not a most critical, as long as gapped just passable, still, if be used in the non-rectilinear groove, wide hinge can be out of shape.The hinge width that is suitable for is preferably the scope at 1.0 to 3.0 millimeters in the scope of 0.5 to 4.0 millimeter.

Be preferably, each hinge between two surfaces, the head degree of depth, apart from each surface at least about 10%, preferably at least about 20%, better at least about 30% place.The distance of hinge from the surface is to use the vertical line that draws to the nearest interface at hinge center from the top on surface to measure.Hinge is positioned at leave the place on the surface of tool head to mean that they are subjected to minimum elongation or compression when head is crooked, has so just improved their durability.In a specific preferred embodiment, tool head has the transverse groove of paired setting, a groove in the every pair of groove is on a surface, and with paired groove in another is directly relative, between them, have one or more hinges and connect all segmentations, make each hinge between two surfaces, and the head degree of depth, apart from each surface at least about 10%, preferably at least about 20%, preferably at least about 30% place.

In second basic step of technology of the present invention, elastomer is expelled in the vacancy space under at least about 245 ℃ of temperature, thus elastomer is fused in the plastic material, but and the joint of formation elastic bending.Be preferably under the temperature in about 245 ℃ to 270 ℃ scopes, be more preferably temperature in about 250 ℃ to the 260 ℃ scopes projectile gonosome of making a bet.Injection temperature is the temperature that elastomer enters mould.Comprise in the typical injection-molded scheme of screw feeding injection barrel that one this temperature can be different with the elastomeric temperature in the cylinder.Preferably cylinder adopts about 210 ℃ to 220 ℃ lower temperature, damages with possibility and the thermic that reduces the elastomer burning, heats final injection temperature by the hot rotor between straight cylindrical nozzle and final injection point.

The preferable condition of other of elastomer injecting step comprises:

A) injection pressure is preferably in about scope of 40 to 70MPa in about scope of 30 to 80MPa, is more preferably in about scope of 50 to 60MPa, and the time of elastomer injection is less than 1 second, is preferably to be less than 0.8 second.Help elastomer to arrive all flexible engaging zones short inject time under required temperature.

B) after elastomer has all been injected, keep-up pressure in about scope of 5 to 15MPa, be preferably the scope 8 to 12MPa, the retention time is between 2 to 5 seconds.

Elastomer is well-known in injection-molded field." elastomer " but but refers to the material of a kind of not only elastic compression but also elastic extension at this term.For purpose of the present invention, suitable elastomer has the elastic modelling quantity less than 500MPa.Has elastic modelling quantity at this used preferable elastomer less than about 300MPa, the thermoplastic elastomer that good especially is has about 30 Shore A to 74 Shore D hardness, such as the polyolefin of styrene-ethylene-butylene-styrene (styrene-ethylene-butylene-styrene (SEBS)), be preferably, except other class elastomer, for example based on Kraton such as polyurethane (second) fat and polyamide ^Those of G also can use.A schematic elastomer is that ' PTS Thermoflex 75 ' is (by (the plastic technologie service of plastics technology mechanism of Germany, germany) sell), it has the elastic modelling quantity (ISO 178) of 100MPa and the hardness (ISO 868) of 80 Shore A.Elastomer PL12291, PL12292 and PL12293 (by Multibase, Saint Laurent Du Pont, France sells) also be suitable at this.Generally, select elastomer identical with the material of head segmentation based on polymeric chemical classes (chemical class), this helps elastomer to be fused in the head segmentation.For example, segment section is when being made by polypropylene right overhead, and elastomer is preferably based on polyolefinic.Also can select elastomer is mixed with suitable manufacturing methods or blowing agent, make them more compressible.Elastomeric color can be with the head segmentation identical, also can be different, obtain the distinguished outward appearance that has clause or pattern thus.In a word, can use more than one elastomer in the instrument.For example in the time need changing its deflection degree gradually along the length of head, this just is well suited for.An approach that reaches this purpose is to use softer elastomer as near the connection means between the free-ended a pair of segmentation of head, uses harder elastomer conduct near the connection means between a pair of segmentation of head handle end.

Elastomer preferably is fused in the adjacent segmentation and/or in the handle, make the elasticity physical efficiency be elongated to its not stressed length about 120%, be preferably about 150%, be more preferably about 200%, elastomer and head segmentation simultaneously be regardless of from.This makes the present invention be specially adapted to constitute the following flexible toothbrush of head that will describe.Degree and the scope of fusion be enough to make elastomer be elongated at least its not stressed length about 120% and elastomer is separated with head segmentation and/or handle.This shows, in any one elastomer/segmentation joint face, in the interfacial area between elastomer and head segmentation or the handle preferably at least about 50%, better fused at least about 75%, especially 100%.

" elastomer does not separate with head segmentation and/or handle " meaning herein is that elastomer can not become and head segmentation and/or handle break away from fully.Even because the partial failure that is connected with the head segmentation of the elastomer also function and/or the globality of entail dangers to instrument, so, even partly disengaging also preferably will be avoided.In preferred embodiment, when elastomer be elongated to its not stressed length at least about 120%, about 150%, better about 200% the time preferably, elastomeric disengaging be lower than interfacial area between elastomer and head segmentation or the handle about 30%, preferably be lower than about 15%, better be lower than about 5%.No matter elastomer is that above-mentioned result should still guarantee owing to a segmentation is extended with respect to linear deflection, bending or the torsional motion of adjacent sectional or handle.Because, some geometry that is connected with handle for segmentation and segmentation or segmentation, or, can change the elongation degree that elastomer passes through the interface for the bending or the twist motion of a segmentation with respect to its next door, so when measuring local the disengaging, be careful.Under the situation that different elastomer extends, the every bit on arbitrary interface all will be measured, and should measure elongation along passing the line that elastomer draws, when instrument is in its static not stress, this line at the some place that will be determined separation perpendicular to the interface.In bending or twisted mode, when relative another of a segmentation moves, but this line offset from perpendicular.

In its whole useful life period, but the instrument with described elastic bending head can bear for example by several thousand caused elastomeric elongations of head-bent.Therefore be preferably, that elastomer and combining of segmentation can be born is elastomeric at least 10000, be preferably at least 25000, be more preferably the loose again loose circulation of stretching, extension of getting back to the repetition of inactive state of the above-mentioned degree of 75000 times extend to.

In the splendid embodiment of this paper, head comprises at least one cannelure, and this cannelure connects the elastomeric strip of horizontally set, so that elastomer in injection-molded process, can flow to another from a bar.Have altogether in the instrument with molded handle one, this cannelure can extend along handle, makes that being commonly used to the supply elasticity body also can be used for elastomer is expelled to vacancy space in the head with the same elastomer injection point in the mould that forms handle.Usually all sites of this cannelure is do not penetrate handle or head complete dark, although be to do like this when needing, for example the end face at handle provides several places relative handle point with the bottom surface.

But the present invention is specially adapted to have the manufacturing of the instrument of elastic bending head." but elastic bending head " is meant when one 3 Newton force in this meaning and is applied to an end of head and the other end when being maintained fixed, the end that applies power is the angle of 2 ° of deflections at least, and when this 3 Newton force was withdrawn, head was got back to its original position under the effect that does not have applied force.The head end that is maintained fixed is limited by the line perpendicular to an axis, and crooked this line contacts first point along this line generation, thereby constitutes the cleaning device such as row's toothbrush bristle.The head end that applies power is the head opposite end in the solstics of bending axis.The angle that head was bent when as above applying one 3 Newton force is called bending angle at this.The distance (x) of measurement between the head free end vertical displacement (y) under the 3 Newton force effects and measurement clamping point and active force just can be measured bending angle easily, and bending angle is derived by relational expression tangent (tan) (bending angle)=y/x.In a preferred embodiment, bending angle is 3 ° at least, is more preferably 5 °, and this angle can be greatly to 15 ° or bigger.

In the preferred embodiment of this paper, instrument comprises a cleaning device on face of head, and this face is spill.In these embodiments, head preferably has one to make the surface of depression can be bent to the bending angle that it becomes the degree of projection.In its inactive state, the surface with head of cleaning device can be along its vertical or horizontal axis depression.For the surface of axle depression longitudinally, radius of curvature can change along the length of head.From 10 to 500 millimeters preferably of radius of curvature, better from 15 to 250 millimeters, especially from 25 to 150 millimeters.

In the use, toothbrush of the present invention can be by being that the action of the traditional type hand of brushing teeth comes cleaning teeth fully, preferably the method for recommending with dental health management board.This instrument can also be a kind of electric toothbrush.

Below in conjunction with accompanying drawing, only being that way of example is described the present invention, in these accompanying drawings:

Fig. 1 is the stereogram of the present invention's one toothbrush, has for clarity sake omitted the part bristle.

Fig. 2 is a partial side view, and it shows the head of the present invention's one toothbrush.

Fig. 3 is a vertical view, and it shows the head bottom surface of the present invention's one brush.

Fig. 4 is the stereogram of the toothbrush that is hinged of the present invention one, in order to be clearly shown that hinge and groove, not shown elastomer.

Fig. 5 is a schematic diagram, and it shows the measuring method of bending angle.

Consult Fig. 1, toothbrush 1 has a resiliency flexible, flat head 2, and this head has end face 3 and the bottom surface 4 that is substantially parallel to each other, and elongated polypropylene handle 5.Head comprises four polypropylene segmentations 6, and first segmentation wherein links to each other with handle 5.These segmentations only link together by the SEBS elastomeric strip with 60 Xiao A hardness.These segmentations 6 vertically order arrangement of axle A-A longitudinally.7 axiss of pitch of crossing head B-B of elastomer extend to bottom surface 4 from end face 3.The pieces of bristle 8 stretches out end face 3.In fact, toothbrush has the bristle that stretches out from each segmentation.End face 3 is the axis A-A slight concave longitudinally, and radius of curvature is about 75 millimeters.Elastomeric strip makes toothbrush head have enough pliabilities, like this head just longitudinally axis up to the crooked and projection that becomes of end face.When doing like this, elastomeric end face elongation.The elastomer of this face is stretched to 200% of its stress-less length and also wants many, but elastomer lost with being connected without any significantly connecting of all segmentations.Head can repeated flex and is got back to inactive state 75000 times, and can not make elastomer and head segmentation that any disengaging is arranged.Handle also comprises same elastomeric regional 9, the handle that has function and attraction with formation.Toothbrush is made like this, and the first step is that injection-molded polypropylene is to form handle 5 and all segmentations 6 earlier, and second step was to inject elastomer in 255 ℃ temperature subsequently, was fused in the polypropylene thus.After the brush cooling, insert in the prefabricated pieces hole with the pieces of binding technology (stapling technique) with bristle.

Consult Fig. 2, the toothbrush head 2 with free end 10 and handle end 11 is integrally formed at an end of handle 5.Head comprises five along the vertical tactic segmentation 6 of head.These segmentations link together flexibly by elastomeric strip 7, and the segmentation near handle end 11 only is connected in handle 5 flexibly by an elastomer.Elastomeric strip 7 passes completely through the axis of pitch of head from the end face to the bottom surface.Width along the elastomeric strip of end face is about 1.2 millimeters, is about 0.8 millimeter along the width of the elastomeric strip of bottom surface.Bristle pieces 8 stretches out the end face of head.Toothbrush is earlier injection-molded successively as mentioned above to be loaded onto bristle subsequently and makes.

Consult Fig. 3, toothbrush head 2 is integrally formed at an end of handle 5.Head comprises four segmentations, and one of them links to each other with handle 5.These segmentations only link together by the SEBS elastomeric strip with 60 Xiao A hardness, and segmentation has the waveform that crosses the head axis of pitch.One cannelure 12 extends along the bottom surface of head and handle, connects all elastomeric strip, and therefore, they can both form from single elastomer injection point.

Consult Fig. 4, a toothbrush 1 has the head 2 co-molded with handle 5, and the end face 3 of head is depression along its longitudinal axis.Elastomer is filled up to form handle in the vacancy 13 of handle.The vacancy is by being connected with each other at the cannelure 12 handle bottom side, that extend to head and connect the transverse groove 14 between all segmentations 6.All segmentations link to each other by thin hinge 15.Elastomer in vacancy and the groove can be from single injection point 16 injections, and its color is different from head material, thereby has any different in appearance.Head has all holes 17 that are arranged on its top surface, to hold the bristle pieces.

Fig. 5 shows the measurement of angle of bend.The first row brush mao mao who leans against the end that is connected in handle 5 restraints 19 and clamps head 2, one 3 Newton force (F) and be applied to relative end.Dotted line is represented the origin-location of the toothbrush head before the power that applies.Measure the vertical displacement (y) of head free end under power F effect, angle of bend can draw by its tangent relationship formula=y/x from the distance (x) between distance y and clamping point and the point of force application.

Claims (7)

1. A process for forming a fully resilient joint in the handle or head of a personal cleansing implement comprising a handle having two ends and a head at one end of the handle, the head comprising a cleaning device, the process Include the following steps: providing a tool blank comprising at least one region of plastics material defining a void space in the head or handle; and The elastomer is injected into the void space at a temperature of at least 245° C., thereby fusing the elastomer into the plastic material, forming an elastically bendable joint. 2. The process of claim 1, wherein the head of the tool includes a resiliently bendable joint. 3. Process according to claim 1 or 2, characterized in that the plastic material is polypropylene. 4. Process according to any one of claims 1 to 3, characterized in that the elastomer is injected at a temperature in the range 245°C to 270°C, better still in the range 250°C to 260°C. 5. A personal cleansing implement having an elongated handle and a head at one end thereof, the head comprising a cleaning device; the head or the handle comprising a plastic material having a Vicat softening point below 245° A resiliently bendable joint between a first region and a second region made of an elastomer, wherein the elastomer is fused into the plastic material, allowing the elastomer to elongate to its unstressed position without detaching from the plastic material 120% of the length. 6. The tool of claim 5, wherein the plastic material is polypropylene. 7. A tool according to claim 5 or 6, characterized in that the elastomer is capable of elongation up to 150%, preferably 200%, of its unstressed length without detaching from the plastic material.

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