WO2011070178A1

WO2011070178A1 - Improvements in or relating to moulded articles

Info

Publication number: WO2011070178A1
Application number: PCT/EP2010/069545
Authority: WO
Inventors: Ian Scrimgeour
Original assignee: SPD Swiss Precision Diagnostics GmbH
Current assignee: SPD Swiss Precision Diagnostics GmbH
Priority date: 2009-12-11
Filing date: 2010-12-13
Publication date: 2011-06-16
Anticipated expiration: 2012-06-11
Also published as: GB0921694D0

Abstract

Disclosed is a moulded component, the component comprising a substrate which has one or more retention details for conferring a frictional engagement with a second component, wherein said retention detail is provided as a protrusion formed on the substrate, such that during moulding of the substrate the retention detail is able to flex about a mould tool to facilitate separation of the substrate and the mould tool, but wherein the degree of flex of the retention detail in the moulded component can subsequently be limited by in-filling free space surrounding the retention detail with a substance of limited compressibility.

Description

Improvements in or Relating to Moulded Articles

Field of the Invention

The present invention relates to an improved method of making an article comprising a moulded component, especially by injection moulding, and to a moulded component or an article comprising the moulded component.

Background of the Invention

It is common to make articles out of a plurality of separate components, one or more of which are formed by the moulding of a synthetic plastics substance. Such moulding techniques frequently comprise one or more of injection moulding, overmoulding or insert moulding.

The separate components of the article then need to be joined or assembled. Many ways of joining the components are known. One of the most popular techniques is the provision of a snap fit, in which a resiliently deformable portion on one component is distorted about a suitably shaped portion on another component and then 'snaps' back towards its original position or confirmation. Snap fits have a number of advantages over other types of connection, but do generally require the provision of more complicated moulds.

Insert moulding is an injection moulding technique, in which a synthetic plastics resin or the like is forced into a cavity and around an insert which is introduced into the cavity prior to moulding. This results in a single object, with the insert substantially encapsulated by the plastic. The insert may itself be a previously moulded synthetic plastics component. The present invention is concerned with improved moulded components and articles, and with methods of making the same.

Summary of the Invention

In a first aspect, the present invention provides a method of making an article comprising a first moulded component, wherein said moulded component comprises a substrate, and wherein said method comprises the steps of:

a) using a first mould tool to mould the substrate, said substrate comprising;

i) one or more retention details for conferring a frictional engagement with a second component, wherein said one or more retention details are provided as protrusion(s) formed on the substrate; and

ii) a pocket of free space adjacent to said one or more retention details,

wherein said pocket is defined partially or wholly by the substrate, and wherein said one or more retention details are configured to flex into said pocket; and

b) separating the first mould tool from the substrate, wherein said one or more retention details flex into the pocket to facilitate separation of the first mould tool from the substrate.

As used herein, the term "component", it is intended to refer to the component after removal or separation from any moulding tool used in manufacture of the component, unless the context dictates otherwise.

Preferably, the substrate additionally comprises a means for receiving at least a part of the second component. This means may comprise a cavity, which is preferably formed during step a) by a mould core provided on the first mould tool.

Preferably, the retention detail protrudes into the cavity. Preferably, the retention detail comprises an arm, which is resiliently deformable. Preferably, the retention detail comprises a recessed portion configured to receive a complementary projection on the second component. The recessed portion is desirably created in the substrate during step a) by a complementary projecting portion on the first mould tool. Typically the projecting portion is formed on the mould core of the first mould tool, such that the recessed portion is formed on the retention detail facing towards or communicating with the cavity of the substrate.

However, the provision of a recessed portion on the retention detail, formed by a complementary projection on the first mould tool, might create a problem in that the projection on the mould tool would engage with the recessed portion of the retention detail, hindering removal of the component from the mould tool. This problem has been encountered previously and a prior art solution to the problem includes the provision on the mould of a retractable portion, such that once the recessed portion has been formed, the responsible projection on the mould is retracted, to allow the component to be removed. However, this considerably increases the complexity of the mould. Another solution that has been adopted in the prior art is to provide a degradable mould e.g. part of the mould is destroyed after moulding (e.g. by melting a wax portion or the like), to allow removal of the component. However, this obviously requires the mould to be reformed or re-made after each moulding and so is not suitable in situations where moulded components are to be mass-produced.

The solution provided by the present invention is to provide a pocket of free space around the retention detail. The pocket of free space is, during the moulding of the substrate, free of material which might obstruct or prevent flexing of the arm of the retention detail during separation of the component and the mould.

The flexibility of the retention detail allows the retention detail to flex outwards into the pocket of free space and disengage from the complementary projecting portion of the first mould tool, to facilitate separation of the first moulded component and the first mould tool after the moulding has been completed. In a preferred embodiment, the one or more retention details communicate with the cavity, such that the mould tool forms, and fits within, the cavity in the substrate during the moulding thereof, and the one or more retention details flex outwards, away from the mould tool, and into the surrounding free space, to facilitate separation of the mould tool and the substrate.

Preferably, the removal of the mould core from the cavity of the substrate causes the one or more retention details to flex away from the cavity, into the pocket of free space. In a preferred embodiment, the flexing of the one or more retention details into the pocket disengages the projection on the mould tool from the recessed portion of the substrate.

The provision of a pocket of free space into which the retention detail can flex in turn provides a further problem. The arm is free to flex by a considerable amount, which means that the fit with the second component is relatively weak and the two components can be readily separated. In some applications a weak fit of this kind may be acceptable but in some other instances requirement for a stronger force to separate the two components may be desirable. An example is the saliva sampling device described in detail in the Examples below, in which it is desirable that a swab portion cannot be readily removed from the handle of the device.

Therefore, it will often be desirable to perform a second moulding step on the substrate in order to infill the pocket of free space around the one or more retention details, to reduce the flexibility of the retention detail (to provide a stronger, more rigid connection with the second component) and/or to provide a smooth, flush finish and/or a watertight coating around the substrate. Thus, in a preferred embodiment, the method of the first aspect additionally comprises the following step; c) partially or wholly filling the pocket with a moulded infill portion.

Preferably, the moulded infill portion is configured to limit the movement of the one or more retention details into the pocket of free space when the first moulded component engages with the second component. The infill portion may comprise a synthetic plastics polymer.

The second moulding step may efficiently be performed by overmoulding the substrate to fill the pocket and form an overmoulded outer layer.

The second moulding step may desirably be performed using a second mould tool which has a mould core very similar to that used in the initial moulding of the substrate, but with one important distinction. The mould core used in the second moulding step should preferably not comprise any complementary projecting portion which might engage with the recessed portion present on the one or more retention details of the substrate. This is because the infilling of the free space around the retention detail, which is accomplished during the second moulding step, significantly increases the rigidity of the retention detail, which is thus no longer readily able to flex to facilitate separation of the component from the mould tool. Thus, the absence of projecting portions on the mould core of the second mould tool which might snag on the retention detail is highly desirable.

The mould core of the second mould tool has an important function of supporting and stabilising the retention detail during the second moulding step. In addition, it is very advantageous that the second mould tool, and more especially the mould core thereof, seals off the recessed portion of the retention detail during the second moulding step, otherwise the material employed in the second moulding step will fill the recessed portion and render it ineffective.

In a preferred embodiment, the retention detail is provided with a feature which forms an engagement, for example a frictional engagement, with the second mould tool during the second moulding step. This helps to keep the retention detail supported and also helps to ensure that the retention detail is correctly positioned during the second moulding step for the mould core to seal off the recessed portion of the retention detail. The frictional engagement may be provided, for example, by a sloped portion on a face or edge of the retention detail which engages with a complementarily reverse sloped portion of the second mould tool. It is therefore preferred that the second mould tool comprises a reverse sloped portion which enters into frictional engagement with a complementary sloped portion on a face or edge of the retention detail.

Alternatively, the further moulding step may be performed by injection moulding. A particularly preferred method of injection moulding is insert moulding, wherein the substrate is used as an insert.

In a further embodiment of the first aspect, the article additionally comprises a second component, and the method of the first aspect additionally comprises the following step: d) forming a frictional engagement between the first moulded component and the second component.

Preferably, this step comprises placing at least part of the second component into the cavity of the first moulded component to form a frictional engagement between the first moulded component and the second component. In one embodiment, the one or more retention details of the first moulded component form a frictional engagement with the second component. Preferably, the complementary projection on the second component engages with the recessed portion on the one or more retention details of the first moulded component. Preferably, this engagement produces a snap fit.

In one embodiment, the invention provides a method of making a moulded component comprising a substrate having one or more retention details for conferring a frictional engagement (especially a snap fit) with a second component, the method comprising the steps of performing a first moulding step to form a moulded substrate as aforesaid, and performing a second moulding step to in-fill the open space in the substrate with moulded material. The second moulding step is conveniently performed by injection moulding. The material used in the second moulding step may be the same as the material used to form the substrate, or may be a different material. In some embodiments, the second moulding step also serves to provide a moulded handle or coating around all, or the majority, of the substrate.

In a further embodiment, the present invention provides a method of making an article, the method comprising the steps of:

(a) forming a first component having a moulded substrate comprising one or more protruding retention details for conferring a frictional engagement, preferably a snap fit, with a second component, with a free space around the retention detail(s);

(b) performing a second moulding step to infill the free space with moulded material; and

(c) forming the second component, and forming a frictional engagement between the first and second components.

The methods of the first aspect of the present invention may optionally comprise further conventional steps, such as the addition of any further components which may be included in the article, and packaging etc., ready for distribution.

In a second aspect, the invention provides a moulded component, the component comprising a substrate, which substrate comprises;

i) one or more retention details for conferring a frictional engagement with a second component, wherein said one or more retention details are provided as a protrusion formed on the substrate; and

ii) a pocket of free space adjacent to said one or more retention details, wherein said pocket is defined partially or wholly by the substrate, and wherein said one or more retention details are configured to flex into said pocket to facilitate separation of the substrate from a mould tool during moulding of the substrate.

The frictional engagement preferably provides a secure fit between the first moulded component and the second component. In preferred embodiments, the one or more retention details form a snap fit with the second component. The substrate of the moulded component typically comprises means for receiving and/or accommodating at least part of the second component. Preferably, the moulded component comprises a cavity to receive at least a part of the second component.

The pocket of free space around the one or more retention details is partially (or wholly) defined by a portion of the substrate, such that the free space around the one or more retention details may take the form of a partially open pocket. Where the substrate comprises a plurality of retention details, the retention details may be able to flex into a common partially open pocket, or each retention detail may be provided with a respective partially open pocket, or any intermediate between these (e.g. two retention details sharing one pocket and two other retention details sharing a further pocket).

In a preferred embodiment, the retention detail will comprise a resiliently deformable arm.

Preferably, the retention detail comprises a recessed portion. The recessed portion is for accommodating a complementary, co-operating projection on the second component, and is configured to receive the complementary projection. The recessed portion is conveniently situated towards or at one end region of the retention detail, preferably towards or at a distal end region. In a particularly preferred embodiment, the recessed portion is situated at a distal end of a resiliently deformable arm. The projection is preferably suitably shaped and dimensioned to be accommodated within the recessed portion and provide a snap fit therewith. The shape of the recessed portion may be any suitable shape e.g. hemispherical, annular, wedge-shaped, trapezoidal or the like. Those skilled in the art will appreciate that the shape of the recessed portion, and of the complementary projection on the second component, may be selected so as to provide a frictional engagement or a snap fit which is essentially permanent (i.e. the two components are not intended to be separated once joined) or to provide a fit which allows for repeated assembly and disassembly of the two components (e.g. where cleaning or maintenance might be expected). Thus the fine detail of the design may depend on the intended application of the moulded component. In one embodiment, an aperture is present in both an upper and a lower portion of the substrate, respectively. Typically, the apertures are aligned such that a support may be inserted through the apertures to support the substrate during moulding. Typically, in this embodiment, the apertures are substantially circular such that a cylindrical tooling feature may be inserted through the respective apertures. The substrate is typically small and thin and is liable to deform and bend to one side under injection pressures experienced during injection moulding. Thus, the provision of an aperture in each of the upper and lower surfaces of the substrate, through which a cylindrical tooling feature may be inserted, assists in the moulding process, such that the substrate may be moulded with minimal deformation.

One embodiment of the second aspect provides a moulded component comprising a substrate which has one or more retention details for conferring a frictional engagement with a second component, wherein said retention detail is provided as a protrusion formed on the substrate, such that during moulding of the substrate the retention detail is able to flex about a mould tool, to facilitate separation of the substrate and the mould tool, but wherein the degree of flex in the moulded component can subsequently be limited by in- filling the free spacing surrounding the retention detail with a solid.

In another embodiment of the second aspect, the present invention provides a moulded component comprising a substrate, having a cavity to receive and accommodate at least part of a second component, the substrate further comprising one or more retention details for conferring a frictional engagement with the second component, the one or more retention details each comprising a flexible arm located within an open pocket within the substrate, and a recessed portion in a surface of the flexible arm facing the cavity, and wherein the flexible arm of the one or more retention details is able to flex outwards away from the cavity. Conveniently there are at least two such retention details, located on opposite sides of an intervening cavity. In a third aspect, the present invention provides a moulded component, the component comprising a substrate which comprises;

ii) a pocket adjacent to said one or more retention details, wherein said pocket is defined partially or wholly by the substrate; and

iii) a moulded infill portion configured to partially or totally fill said pocket and to limit the movement of said one or more retention details into said pocket when the substrate frictionally engages with the second component.

The infill portion is conveniently formed in a second moulding step, (conveniently by injection moulding or overmoulding), after the moulded component has been removed from the moulding tool used in an initial moulding step.

The material in the infill portion serves to limit the flexibility of the retention detail, and thus increases the force required to disrupt the fit between the first moulded component and the second component.

The rigidity of the substance selected as the infill material thus determines, at least in part, the degree of flexibility allowed to the retention detail in the finished component. It is possible (but not preferred) that the infill material is highly rigid, effectively locking the retention detail in position, in which case the second component may advantageously comprise a resiliency deformable portion to facilitate engagement with the retention detail.

In other embodiments, the infill material may be relatively flexible so as to allow greater movement of the retention detail. It may be desirable for the substrate to include a region which partially defines the free space around the one or more retention details and which is substantially aligned with the axis of movement of the retention detail(s) when it flexes. This free space-defining or pocket-defining region serves to provide support and rigidity if the infill substance is not of sufficient rigidity, in isolation, to provide the desired degree of resistance to the movement of the retention detail. Thus, the infill material may be at least partially sandwiched between the retention detail and an outer, pocket-defining portion of the substrate.

Preferably, both the substrate and the infill portion are moulded from a synthetic plastics polymeric material. Suitable materials will be apparent to those skilled in the art. In one embodiment the substrate comprises polypropylene. Other suitable materials include without limitation, polyamide, polyethylene, polyethylene terephthalate, acrylonitrile butadiene styrene, acrylonitrile styrene acrylate, polycarbonate, polystyrene and high impact polystyrene. In one embodiment the infill material or outer layer material comprises thermoplastic elastomer (TPE). Other suitable materials include, without limitation, polypropylene, thermoplastic polyurethane, silicone, synthetic rubber, polyamide, polyethylene, polyethylene terephthalate, acrylonitrile butadiene styrene, acrylonitrile styrene acrylate, polycarbonate, polystyrene and high impact polystyrene.

The infill material is preferably provided by overmoulding or insert moulding the initial moulded component, as discussed above. One embodiment of the present invention provides a moulded component generally as defined in relation to the second aspect of the invention, but wherein the free space around the retention detail(s) has been at least partly filled by an infill material, which is conveniently a synthetic plastics polymer.

Another embodiment of the third aspect provides a moulded component which, initially, is in accordance with the second aspect of the invention, comprising a substrate having one or more retention details for conferring frictional engagement (especially a snap fit) with a second component, but wherein deformation of the retention detail is limited by the provision of infill material which is formed in a second moulding step.

In a preferred embodiment, the infill material is at least partly sandwiched between the retention detail and an outer, pocket-defining, portion of the substrate. In preferred embodiments, the substrate is additinally comprises an outer layer or a coat around the substrate, so as to confer a smooth exterior finish and to fill any apertures present in the substrate, as well as providing the infill material to fill the free space around the retention detail(s) in the substrate. Desirably the infill material will completely fill the pocket of free space initially present in the substrate. It is a particular advantage of the invention that different materials may be used to form the substrate and to form the overmoulded outer layer or coat. Thus, for example, the material used to form the substrate may be relatively rigid to provide adequate structural strength, whilst the synthetic plastics material used for the overmoulding may be selected to provide an aesthetically pleasing tactile surface for the moulded article. The substrate may be translucent, whilst the overmoulding may be opaque and, especially, coloured. The overmoulding may, conveniently, be provided over the majority of the surface area of the substrate and may be provided, in some embodiments, over substantially all of the substrate.

In a fourth aspect, the present invention provides an article comprising;

a) a first moulded component in accordance with the third aspect; and

b) a second component;

wherein said first moulded component is frictionally engaged with said second component.

One embodiment of the fourth aspect provides an article comprising a moulded first component in accordance with the third aspect of the invention and a second component in frictional engagement (preferably a snap fit) with the moulded first component. The second component conveniently is also moulded from a synthetic plastics material.

The invention is especially useful in providing articles with a smooth, substantially, flush, exterior surface, essentially free of holes or sharp edges, and/or where a water-tight coating is required around a moulded component having an internal cavity. Further, the invention is especially useful where a strong attachment is required between the first and second components (i.e. where it is not intended that the two components should be separated after assembly). For example, the article might be for use in medical or clinical applications where a smooth finish is desired to inhibit the accumulation of dirt and/or micro-organisms.

Preferably, the article is a sample collection device. In such a device, the first moulded component may comprise a handle, and the second moulded component may comprise a swab for collection of the sample.

In one embodiment, the article of the invention is suitable for use in a sample collection device for the collection of oral fluid from the oral cavity of a subject. The device comprises a first component, which comprises a substrate as defined previously, which is overmoulded in a second moulding step to provide a handle around the substrate and to fill in the pocket of free space around the retention details. A second component is a moulded synthetic plastics support which is pushed into a snap fit with the substrate at one end, and at the other is attached to a swab, which comprises compressible porous foam for absorbing a fluid sample, such as saliva. In such an embodiment a strong snap fit attachment is required between the first component (a handle) and the second component (a saliva-absorbing swab component), to prevent the swab component becoming separated from the first component during use.

Preferably the porous collector comprises open cell foam. More preferably, the porous collector comprises polyvinyl alcohol (PVA) or the like. In a preferred embodiment, the foam is dye-cut to size and subsequently expanded to assume its full thickness upon hydration thereof.

Preferably, the moulded substrate/handle article is wholly or partially disposable after a single use. Conveniently, the moulded article of the invention is for use in a system or device for the rapid, safe and non-invasive collection of a sample from a subject, such as for the collection of a saliva sample. Such devices are ideally suited for use in the home, office or work environment, or for point-of-care purposes and do not require laboratory facilities or the presence of trained medical personnel. In particular, the device is suitable for self-use by the subject and may be used by adults or children.

As used herein, the term "oral fluid" refers to one or more fluids found in the oral cavity of a subject, either individually or in combination. These include, but are not necessarily limited to, saliva and mucosal transudate. The oral fluids may comprise a combination of fluids from a number of sources (e.g. parotid, submandibular, sublingual, accessory glands, gingival mucosa and buccal mucosa).

The term "subject", as used herein, refers to a test subject whose oral fluid is to be collected for testing. Preferably, the subject is a mammal. Most preferably, the subject is a human.

Preferably, oral fluid collected by a moulded article in accordance with the present invention is assayed to detect the presence of one or more analytes. More preferably, oral fluid is assayed to detect the presence of one or more antigens. Most preferably, oral fluid collected is assayed to detect the presence of one or more Strep A antigens.

As used herein, the term "analyte" is used to denote an unknown substance that is present in a liquid medium.

Examples of other products for which the component, moulded article, and the method of manufacture of the present invention may be advantageous include medical device casings, electrical goods and mobile phones, PDAs, calculators and the like.

A fifth embodiment of the present invention provides a method of making a moulded component in accordance with the second or third aspects defined above, or a method of making an article in accordance with the fourth aspect defined above. Preferably, said method is in accordance with the first aspect of the present invention. More specifically, the invention provides a method of forming a component comprising a substrate, the substrate being in accordance with the first aspect defined above, the method comprising the steps of:

using a mould tool initially to mould a polymer material (such as a synthetic plastics material) to form a substrate, the substrate having one or more protruding retention details for conferring a frictional engagement with a second component, and a free space around the retention details formed in the substrate which free space allows the one or more retention details to flex about the mould tool to facilitate separation of the moulded component and the mould tool when the moulding is completed; and separating the moulded component and the mould tool.

In a sixth aspect, the invention provides a set of mould tools for use in performing the moulding method of the invention, the set of mould tools comprising at least two mould cores, wherein a first mould core is shaped to form and define a cavity in a substrate in a first moulding step, and comprises a projecting portion so as to form a complementary recess in a retention detail provided on the substrate; and wherein a second mould core has a portion which enters the cavity of the substrate in a second moulding step, which portion is essentially or substantially identical to that part of the first mould core which forms the cavity, except that the second mould core does not possess a projecting portion which is complementary to the recess provided in the substrate.

It is a preferred feature that the second mould core has a sloped portion, preferably on a face or edge thereof, which enters into frictional engagement with a complementarily reverse sloped portion of the retention detail provided on the substrate. The frictional engagement serves to support the retention detail during the second moulding step and also helps to maintain the retention detail in the desired position during the second moulding step.

For the avoidance of doubt, it is hereby expressly stated that any feature described herein as "preferable", "desirable", "convenient", "advantageous" or the like may be present in the invention in isolation or in any combination with any one or more other features so described, unless the context dictates otherwise, and thus passage constitutes explicit disclosure of such combinations. Further, features which are preferred, etc., for one aspect of the invention will generally also be preferred in other aspects of the invention, unless the context dictates otherwise.

All the features of each embodiment described above apply mutatis mutandis to all other embodiments of the present invention

Description of the Figures

Figure 1(a) is a partially exploded view of an article in accordance with the invention, comprising first and second moulded components which are assembled with a snap fit;

Figure 1(b) shows the article with the first and second components assembled together;

Figure 2 is a sectional view showing a substrate in accordance with the invention moulded around a mould core;

Figure 3 is a view, to a different scale, showing a detail from the substrate illustrated in Figure 2;

Figure 4 is a perspective view, partially cut away, showing a detail from the substrate illustrated in Figure 2;

Figure 5 shows a sectional view of the substrate, illustrated in Figure 2, in the process of being overmoulded, whilst supported on a mould tool comprising a mould core; and

Figure 6 is a perspective view, partially cut away, corresponding to the detail illustrated in Figure 4, but after the substrate has been overmoulded. Detailed Description of an Embodiment

The various aspects of the invention will now be described with reference to a particular embodiment in which a moulded article is used as a device for obtaining a sample of saliva.

Referring to Figure 1 , the device comprises two moulded components formed by injection moulding of synthetic plastics materials. The first component (2) comprises a substrate, which is then overmoulded to form an overmoulded substrate (4). The second component (6) comprises a compressible porous foam swab element (8) for absorbing saliva from the mouth of a subject. The substrate (2) is formed with a central cavity, into which an end of the second component is introduced. The second component is formed with a projecting wing (10) at each side, and these point backwards, away from the relative direction of movement when the second component is inserted into the cavity in the substrate.

The substrate is provided with two retention details, as best observed in Figures 2 and 3, and these serve to provide a snap fit with the backward projecting wings (10) present on the second component. In view of the intended use of the article, it is important that the snap fit is strong, otherwise the second component may inadvertently become detached from the first component whilst the saliva sampler is being manipulated in a subject's mouth.

The substrate, and its method of manufacture, will now be described in greater detail.

Referring to Figure 2, the substrate is formed by injection moulding using a mould tool, which comprises a mould core (12). The mould core (12) creates a central cavity in the substrate. On each of two opposed sides of the cavity is a retention detail, which comprises a relatively resiliently deformable arm (14). Towards a distal end of the deformable arms (14) is a recessed portion, which is formed by a complementary projecting portion provided on the mould core (12). Outside the deformable arms (14) are bridging portions or pocket-defining portions (16), which serve to define a respective partial pocket (18) with free space around each deformable arm (14).

Referring to Figures 3 and 4, the retention details and the associated pockets can be seen more clearly. In particular, in Figure 4, the recessed portion (20) formed in the retention detail is apparent. The recessed portion is substantially wedge-shaped, with the fat end of the wedge towards the distal end of the arm (14), and the thin end of the wedge proximal thereto.

As shown in Figure 2, once the substrate has been moulded it is removed from the mould core (12), the direction of relative movement of the mould core (12) being indicated by the large arrow, the relatively resiliently deformable arms (14) are able to flex outwards, in the direction indicated by the small arrows, into the free space in the respective pockets (18), which is not filled with moulded material. This outward flexing of the arms (14) enables the recessed portions (20) to disengage from the complementary projecting portions on the mould core (12) responsible for moulding the recessed portions. This facilitates separation of the mould and the substrate.

It is not helpful for the substrate to have arms (14) with such ease of movement, because this would not provide the desired strong snap fit with the second component. In addition, it is not desirable to have an irregular outer surface, since this would feel unpleasant when the saliva sampler is introduced into a subject's mouth. Also it is desirable, for various reasons, to exclude saliva or other fluid from the interior cavity of the substrate. All of these issues can be simultaneously addressed by overmoulding the substrate, or using the substrate as an insert in an insert moulding process, to fill in the free space around the retention details and provide a substantially continuous, smooth outer layer.

As shown in Figure 5, the overmoulding of the substrate may be accomplished using a second mould tool having a mould core (40) very similar to that of the mould core (12) used for the initial moulding of the substrate. However there is an important distinction, in that the mould core (40) does not have projecting portions which engage with the recessed portions (20) of the retention details. Accordingly, separation of the overmoulded substrate from the mould core (40) can be achieved in a facile manner without requiring any outward flexing of the deformable arms (14).

Importantly, although not readily apparent from the drawings, the mould core (40) seals off the recessed portions (20), and so prevents them from being filled with plastics material during the overmoulding step.

In addition, the mould core supports the deformable arms during the overmoulding and helps to keep them in the desired position. To assist in this, the mould core (40) has an angled surface which projects over a co-operating angled surface (22) (best seen in Figure 3) at the distal end of the deformable arm (14). The frictional engagement between the respective angled surfaces helps to resist displacement of the deformable arms by the incoming synthetic plastics material.

As seen in Figure 5 and 6, the overmoulding material (24) serves to fill in the pockets (18) around the deformable arms (14) to confer the desired degree of rigidity for the deformable arms, and also to form a substantially continuous, smooth outer layer or coat around the substrate, which acts as a handle for the article when in use.

Claims

1. A method of making an article comprising a first moulded component, wherein said moulded component comprises a substrate, and wherein said method comprises the steps of:

a) using a first mould tool to mould the substrate, said substrate comprising;

ii) a pocket of free space adjacent to said one or more retention details, wherein said pocket is defined partially or wholly by the substrate, and wherein said one or more retention details are configured to flex into said pocket; and

b) separating the first mould tool from the substrate, wherein said one or more retention details flex into the pocket to facilitate separation of the substrate from the first mould tool.

2. The method of claim 1 wherein said substrate additionally comprises a means for receiving at least a part of the second component.

3. The method of claim 2 wherein said means for receiving at least a part of the second component comprises a cavity formed in the substrate.

4. The method of claim 3 wherein said cavity is formed by a mould core.

5. The method of any preceding claim wherein the retention detail comprises a resiliently deformable arm.

6. The method of any preceding claim wherein the retention detail comprises a recessed portion configured to receive a complementary projection on said second component.

7. The method of claim 6 wherein the recessed portion is formed by a

complementary projection on the mould tool.

8. The method of any of claims 4 - 7 wherein removal of the mould core from the cavity of the substrate causes the one or more retention details to flex into the pocket.

9. The method of any of claims 7 or 8 wherein the flexing of the one or more retention details into the pocket disengages the projection on the mould tool from the recessed portion of the substrate.

10. The method of any preceding claim additionally comprising the step of: c) partially or wholly filling the pocket with a moulded infill portion.

11. The method of claim 10 wherein the moulded infill portion is configured to limit the movement of said one or more retention details into said pocket when the moulded component engages with the second component.

12. The method of claims 10 or 11 wherein said infill portion comprises a synthetic plastics polymer.

13. The method of any of claims 10 to 12 wherein step c) comprises overmoulding the substrate to fill the pocket and form an overmoulded outer layer.

14. The method of claim 13 wherein the overmoulded outer layer and the substrate comprise different materials.

15. The method of claim 13 or claim 14 wherein step c) comprises the use of a second mould tool which comprises a portion essentially or substantially similar to the first mould tool used in steps a) and b), but which does not comprise a complementary projection portion to engage the recessed portion of the retention detail.

16. The method of claim 15, wherein the second mould tool comprises a reverse sloped portion which enters into a frictional engagement with a complementary sloped portion on a face or edge of the retention detail.

17. The method of any of claims 10 to 12 wherein step c) comprises insert or injection moulding.

18. The method of any of claims 10 - 15 wherein said article additionally comprises a second component and wherein said method additionally comprises; step d) forming a frictional engagement between the moulded component and the second component.

19. The method of claim 18 wherein step d) comprises placing at least part of the second component into the cavity of the first moulded component to form a frictional engagement between the first moulded component and the second component..

20. A moulded component, the component comprising a substrate, which substrate comprises;

21. A moulded component, the component comprising a substrate which has;

i) one or more retention details for conferring a frictional engagement with a second component, wherein said one or more retention details are provided as a protrusion formed on the substrate; and ii) a pocket adjacent to said one or more retention details, wherein said pocket is defined partially or wholly by the substrate; and

22. The moulded component of claim 21 wherein said infill portion comprises a synthetic plastics polymer.

23. The moulded component of any of claims 20 to 22 wherein said substrate comprises a means for receiving at least part of the second component.

24. The moulded component of claim 23 wherein said means for receiving at least part of the second component comprises a cavity formed in the substrate.

25. The moulded component of any of claims 20 to 24 wherein the retention detail comprises a resiliency deformable arm.

26. The moulded component of any of claims 20 to 25 wherein the retention detail comprises a recessed portion configured to receive a complementary projection on said second component.

27. An article comprising;

a) a first moulded component as claimed in any of claims 21 to 26; and b) a second component

28. The article of claim 27 wherein said article is a sample collection device.

29. The article of claim 28 wherein the first moulded component comprises a handle and wherein said second component comprises a support and a swab for collection of the sample.

30. A moulded component substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.

31. An article substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.

32. A method of making an article substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.