GB2550331A

GB2550331A - Process

Info

Publication number: GB2550331A
Application number: GB1608243.0A
Authority: GB
Inventors: Rance Steven
Original assignee: Traymate Products Ltd
Current assignee: Traymate Products Ltd
Priority date: 2016-05-11
Filing date: 2016-05-11
Publication date: 2017-11-22
Anticipated expiration: 2036-05-11
Also published as: GB201608243D0; GB2550331B

Abstract

A process for manufacturing an anti-slip article such as a shower tray comprises the steps of: applying an anti-slip mixture to the surface of a male master mould; allowing the mixture to set; making a female mould from the anti-slip coated master mould; and, producing the anti-slip article from the female mould. The mixture comprises at least two particulate materials, including a first particulate material having a first mean particle size, and a second particulate material having a second mean particle size, wherein the second particle size is greater than the first. The mixture further includes at least one resin and a catalyst or curing agent. The particulate materials may be selected from sand or crushed stone, gravel or tree-nut by-products. The resin may be a polyester resin. The anti-slip mixture may be applied to the master mould by rolling, painting or spraying. The female mould may have a multi-layered structure comprising at least one gel coat layer.

Description

Process

Field

The present invention relates to a process for manufacturing anti-slip articles and particularly anti-slip drain bases such as shower trays. The invention further relates to the articles and particularly shower trays provided by this process.

Background

It is known to provide a drain base for a shower, i.e. shower tray, that is generally formed from one or more hard-moulded resin and aggregate materials so as to provide enough structural strength to support the weight of users and also provide a configuration suitable for drainage of water to a separate or integrated drain aperture.

Water itself can create slippery conditions and with the general use of detergents and soaps in shower products, a flat-surfaced shower tray may become dangerous to the user. Likewise articles incorporating similar drain bases that the user may need to traverse and/or that must bear some or all of the user’s weight, for example bath tubs, baby baths etc.

To address this problem undulations such as ribs or dimples are sometimes provided in the surface of such drain bases in order to improve user grip. See, for example US 2,809,380. Other approaches to this problem include applying a coating layer to the surface as in US 3,688,740, or integrating tactile elements through apertures in the drain base, as in GB 2436922.

There is a continuing need for integrated and separate drain bases, and especially shower trays, that can provide excellent anti-slip performance according to the British standard test, BS-7976-2.

Summary of Invention

In a first aspect, applicable to all embodiments, the invention provides a process for manufacturing an anti-slip article comprising: (i) applying an anti-slip mixture to the surface of a male master mould; (ii) allowing said anti-slip mixture to set, to provide an anti-slip-coated male master mould; (iii) making a female mould from the said anti-slip-coated male master mould; (iv) producing said anti-slip article from said female mould; wherein said anti-slip mixture comprises: (a) at least two particulate materials, including a first particulate material, A1, having a first mean particle size, P1, and a second particulate material, A2, having a second mean particle size, P2, wherein A1 and A2 may be the same or different, and wherein P2 is greater than P1; (b) at least one resin; and (c) a catalyst or curing agent.

In a second aspect, applicable to all embodiments, the invention provides an antislip article obtained by the process of the invention.

In a third aspect, applicable to all embodiments, the invention provides the use of an anti-slip mixture comprising: (a) at least two particulate materials, including a first particulate material, A1, having a first mean particle size, P1, and a second particulate material, A2, having a second mean particle size, P2, wherein A1 and A2 may be the same or different, and wherein P2 is greater than P1; (b) a resin; and (c) a catalyst or curing agent in the manufacture of an article having anti-slip performance of at least 40, preferably at least 45, more preferably at least 47, as measured by the British standard anti-slip test, BS-7976-2. Most preferably said anti-slip performance is provided under wet conditions.

Detailed Disclosure

The process of the present invention provides a high-level of anti-slip performance to the gel coated surface of a moulded anti-slip article by means of the moulding process. This does not require application of an additional anti-slip layer or coating to the moulded product. The anti-slip property is integral to the moulding process and does not require a secondary process to be carried out on the moulded article.

The anti-slip surface is provided by means of an anti-slip mixture comprising a combination of particulates and resin. The anti-slip mixture is applied to a standard male master mould of the range and size appropriate to the article which is to be produced as an anti-slip article.

Once the anti-slip mixture has set, the anti-slip-coated male master mould is ready for use as the “Former” or “Pattern”. “Former” and “Pattern” are other names for the anti-slip-coated male mould.

The mixture of particulates in the anti-slip mixture creates a bonded and controlled surface on the Former.

From the Former, a first female mould is made. This can be used as a master mould, to produce further male moulds, and/or can be used as a production mould to provide anti-slip articles such as shower trays.

Additional female production moulds can be made from the Former.

Anti-slip articles, such as shower trays, can then be manufactured from the said female moulds.

The articles, especially shower trays, produced from the female master and/or production moulds are capable of achieving an anti-slip/resistance rating on an independently verified BS-7976-2 Slip test of at least 40 and preferably at least 45, more preferably at least 47. Preferably such performance levels are provided under wet conditions.

For example, the general process for making an anti-slip shower tray may be as follows: 1. A male master mould of the type and size which is to be produced in antislip is made to standard Specification. 2. The surface of the male master mould is cleaned, for example with acetone and then a mould cleaning agent, in preparation for the application of the anti-slip mixture, 3. A measure of resin is weighed into a mixing pot along with a combination of various grades of particulates, such as spherical aggregates, for example sand or crushed tree-nut by-products. This is carefully mixed together. The appropriate amount of peroxide catalyst is added to ensure a working time of 20 minutes before the anti-slip mixture hardens. 4. The anti-slip mixture is applied evenly to the surface of the male master mould. 5. Once the anti-slip mixture has set, the surface is treated with multiple applications of mould release agent, for example up to six applications. The Former/Pattern is now completed and ready for a female mould to be made from it. 6. A female mould is made from the Former/Pattern to the standard specification according to the type and size of tray to be produced. The inverse of the anti-slip surface structure is now incorporated into the surface of the female mould. This is the first Production mould. 7. Upon completion, the female mould is treated with multiple applications of mould release agent, for example up to six applications. This prepares the female mould for the production of shower trays or the optional production of a new male master mould. 8. Optionally, a new male master mould can be made from the female mould, to standard specification, prior to its use for producing shower trays. Following the production of the new male master mould, the female mould would be cleaned with mould cleaner and multiple coats of mould release agent, for example up to six coats, would be applied. The mould would then be ready for production of shower trays as set out in step 9. 9. After step 7, or after optional step 8, shower trays incorporating an anti-slip surface are produced from the female mould. These are produced in accordance with standard stone resin casting industry practices and using the same general method as gel-coated shower trays which are not anti-slip.

In the shower trays of the invention, the gel-coat forming the upper portion of the shower tray has an integrated anti-slip surface, following the contours of the female mould. This provides superior anti-slip properties, as measured using the British standard test, BS-7976-2.

The components and steps of the invention are described in more detail below.

The description of each feature, e.g. definition of each individual component and/or step, applies equally to all aspects and embodiments of the invention, even where described only with reference to one aspect or embodiment of the invention. Features described only with reference to one aspect or embodiment also apply with respect to other aspects and embodiments of the invention.

The term “comprises” is used here as meaning “including but not limited to”. This term is also intended herein to encompass embodiments that consist of the listed features. For example, the anti-slip mixture comprising (a), (b) and (c) also discloses the anti-slip mixture consisting of (a), (b) and (c).

Moulds

The process of the invention must start from a male master mould in order to provide a production mould having an indented surface. This provides the surface contouring in the final article which is believed to provide the superior anti-slip properties. The production moulds are female moulds. Starting with a female master mould would lead to the production mould having a raised surface. This would result in an indented surface in the final article which would not provide effective anti-slip properties. A “master” mould is a mould from which other moulds may be produced. A master mould may preferably be adapted by means of surface coating in order to provide a production mould having particular surface contours or structure. A “male” mould is a mould which is at least partially convex, i.e. extending outward. A male mould is suitable for producing an article or a corresponding female mould which is at least partially concave, i.e. hollowed inward. Typically the male moulds are used to produce female moulds or articles by a process of additive layering onto the male mould, also known as a laminating process. A “female” mould is a mould which is at least partially concave, suitable for producing an article or a corresponding male mould which is at least partially convex. Typically the female moulds are used to produce male moulds or articles according to the invention by a casting process or by a combination of laminating and casting processes.

In the process of the invention the female moulds are produced from male moulds. At least one female mould is produced from the male master mould. The female moulds can be master moulds or production moulds. Preferably at least the first female mould produced from the anti-slip-coated male master mould can be used as both a master mould and a production mould.

The female moulds used in the process of the invention may be suitable for producing articles such as drain bases having a separate or integrated drain aperture. Preferably the articles comprise or consist of a drain base having an integrated drain aperture. Most preferably the articles comprise or consist of a shower tray.

Preferably the articles of the invention are produced by casting from a female mould.

Anti-slip mixture

The anti-slip mixture comprises: a) at least two particulate materials, including a first particulate material, A1, having a first mean particle size, P1, and a second particulate material, A2, having a second mean particle size, P2, wherein A1 and A2 may be the same material or different materials, and wherein P2 is greater than P1: (b) a resin; and (c) a catalyst or curing agent.

Suitable particulate materials include aggregates, for example spherical aggregates. Typical particulate materials suitable for use in the process of the invention include sand products and/or crushed tree-nut by-products. For example natural sand, artificial sand, crushed stone sand, crushed gravel sand, fine-crushed tree nut by-products, or mixtures thereof are typical fine particulates useful as the first particulate material A1. Particulates such as natural sand, artificial sand, crushed gravel, crushed stone, partially crushed gravel or stone, medium-crushed tree nut by-products, or mixtures thereof, are typical medium particulates useful as the second particulate material A2.

The first and second particulate materials, A1 and A2 can be the same material or different materials. In a preferred embodiment applicable to all aspects of the invention, A1 and A2 are both crushed tree nut by-products, or are both sand products.

The preferred shape of a single particle in the particulate materials useful in the current invention is substantially spherical. The overall shape of the particles is, however, normally not extremely critical, thus, the particles can have other types of rounded shapes, e.g. ellipsoid, droplet and bean forms. However, for certain applications it may be preferred that at least 95% of the particles are substantially spherical. In the present context the terms "particle diameter" and "particle size" are used interchangeably and relate to the diameter of a circle which may be made around the particle and therefore, may be regarded as the diameter of the particle on the widest part of the particle.

The first and second particulate materials A1 and A2 have different mean particle sizes. The mean particle size of A1 (P1) is smaller than the mean particle size of A2 (P2).

Typically the mean particle size P1 falls within the range from 200 pm to 850 pm and the mean particle size P2 falls within the range from 800 pm to 1300 pm. Preferably the mean particle size PI falls within the range from 260 pm to 840 pm, for example from 400 pm to 650 pm, such as approximately 500 pm, and the mean particle size P2 falls within the range from 840 pm to 1250 pm, for example from 950 pm to 1150 pm, such as approximately 1000 pm.

The mean particle size differential is the difference in mean particle size between A1 and A2, i.e. the difference between PI and P2, expressed as the ratio P1:P2.

The mean particle size differential may preferably be in the range from 10:11 to 10:65. More preferably the mean particle size differential may be in the range from 10:14 to 10:28, such as 10:18 to 10:22, e.g. approximately 1:2 (i.e. 10:20). For example, if PI were to be 450 pm and P2 were to be 1100 pm, the mean particle size differential, P1:P2, would be 450:1100, i.e. approximately 10:24.

The mean particle size as defined herein is the volume-average mean particle size measured by Dynamic Light Scattering, such as by using a Coulter LS 230 Laser Light Scattering Particle Sizer.

Fundamentally the expression of particle size and particle size distribution in this context is by volume, based on the general understanding in the technical field and as described by various instrument manufacturers in their Operators Guides, such as in “A Guidebook to Particle Size Analysis” by Horiba Instruments, which describes the measurement of particle size distribution by the aid of light scattering.

This means that when the result indicates, for example, that 11% of a distribution is in the size category 200-300 pm, this means that the total volume of all particles having diameters in that range (within the size category 200-300) represents 11 % of the total volume of all the particles in the distribution. The volume-average mean particle size (or volume-average mean particle diameter) referred to in the present context relates to the volume mean diameter labelled "D(4,3)" by Horiba.

Whenever a particle size range is referred to such as "the particles have a particle size distribution in the range of X-Y pm" it is meant to be understood as at least 90 % of the total volume of particles have a diameter in the range of X-Y pm, such as at least 95%, e.g. at least 98%, such as at least 99%.

Preferably A1 may be a fine particulate material, i.e. having a particle size distribution in the range from 200 pm to 850 pm. Preferably A2 may be a medium particulate material, i.e. having a particle size distribution in the range from 800 pm to 1300 pm. For example, when A1 and A2 are both crushed tree-nut by-products the particle size distribution for A1 may typically be 260-840 pm and for A2 may typically be 840-1250 pm.

Particle size distribution may be determined by sieve analysis using standard test sieves and methods according to BS EN 933-1. Preferably the particle size and particle size distribution are determined by light scattering techniques such as dynamic light scattering.

Without being bound by theory, it is believed that having at least two particulate materials of differing mean particle sizes is largely responsible for the improved anti-slip properties in the final article.

The anti-slip mixture can comprise more than two particulate materials. It is believed that there is no upper limit to the number of different mean particle sizes that can be combined to provide anti-slip properties according to the invention.

It is preferred that no more than six particulate materials are included in the anti-slip mixture, i.e. no more than six materials having different mean particle sizes, PI to P6. More preferably no more than four materials having different mean particle sizes, PI to P4 are included. Even more preferably the anti-slip mixture contains no more than two or three particulate materials having different mean particle sizes, PI to P3. Most preferably the anti-slip mixture contains two particulate materials, A1 and A2, having different mean particle sizes PI and P2.

The anti-slip mixture may comprise 5-35% particulate materials by total weight of components (a) and (b) in the anti-slip mixture, i.e the total weight of particulate materials and resin. Preferably the anti-slip mixture comprises 10-30 wt.% particulates, more preferably 12-25 wt.%, even more preferably 16-20 wt%, such as approximately 18 wt%, by total weight of components (a) and (b) in the anti-slip mixture.

The ratio of the first particulate material, A1, to the second particulate material, A2, used in the anti-slip mixture may be in the range from 4:1 to 16:1 by weight, preferably in the range from 6:1 to 14:1 by weight. More preferably the ratio of A1 :A2 by weight may be in the range from 8:1 to 12:1, for example approximately 10:1 by weight. For example, an anti-slip mixture containing 20 g A1 and 2 g A2 has an A1:A2 ratio of 10:1 by weight.

In a preferred embodiment applicable to all aspects of the invention, the amount of the second particulate material (A2) in the anti-slip mixture is in the range 0.5-5%, preferably 1-3% for example approximately 2%, by total weight of components (a) and (b) in the anti-slip mixture.

In addition to the at least two particulate materials, A1 and A2, the anti-slip mixture comprises at least one resin.

Typical resins suitable for use in the anti-slip mixture according to the invention may be low styrene emission, orthophthalic-based unsaturated polyester resins. For example, PALATAL® U 541 TV-05, PALATAL® U 541 TV-11, PALATAL® U 570 TV-04, PALATAL® U 569 TV-03, SYNOLITE® 6060-P-1, SYNOLITE® 2020-P-1, ATLAC 580 ACT, or mixtures thereof.

The anti-slip mixture may comprise 65-95% resins by total weight of components (a) and (b) in the anti-slip mixture, i.e the total weight of particulate materials and resins. Preferably the anti-slip mixture comprises 90-70 wt% resin, more preferably 88-75 wt.%, even more preferably 84-80 wt%, such as approximately 82 wt%, by total weight of components (a) and (b) in the anti-slip mixture.

The anti-slip mixture can optionally contain fillers. The anti-slip mixture may preferably contain no more than 20% fillers, more preferably no more than 15% fillers by super-addition, for example 1-10% fillers. By “super-addition” is meant that the filler(s) are added in addition to the total of components (a) and (b), particulates and resins, that is defined herein as making up 100 parts by weight of the anti-slip mixture prior to addition of (c) catalyst or curing agent. Suitable fillers include talc, carbon black, natural mineral fillers and synthetic mineral fillers. Preferably if fillers are included these will have a particle size distribution corresponding to that of the first particulate material A1.

In all aspects of the invention the anti-slip mixture comprises (c) a catalyst or curing agent. A suitable catalyst is 2% peroxide catalyst, typically added in sufficient quantity to ensure a working time of 10 to 30 minutes, preferably 15 to 25 minutes, for example around 20 minutes, before the anti-slip mixture begins to set (cure or harden). The necessary amount of catalyst is within the knowledge of the skilled worker in this field.

Typically the anti-slip mixture contains from 0.5 wt.% to 5 wt.%, more preferably from 1 wt.% to 3.5 wt.%, of catalyst or curing agent, by total weight of components (a), (b) and (c) in the anti-slip mixture.

The anti-slip mixture is formed by combining the particulate materials and resins in the appropriate quantities as defined herein, together with the optional fillers if present. These components may be combined by hand mixing or mechanical mixing, preferably by mechanical mixing. The particulate materials and resins are mixed until the particulates are distributed throughout the resins in an approximately even distribution. The skilled worker can assess this by eye.

Once the particulates are evenly distributed throughout the resin then the catalyst or curing agent is added and combined by further mixing.

Conditions for the addition and mixing of the catalyst or curing agent are within the knowledge and ability of the skilled worker in the field. The components may be added and mixed by any suitable method according to the art. Typically the catalyst or curing agent is added at room temperature in air and mixed by hand. Mechanical mixing is also possible.

Anti-slip-coated male master mould

The surface of the male master mould may optionally be cleaned before application of the anti-slip mixture. For example acetone may be used to clean the surface of the mould.

The anti-slip mixture is applied to the male master mould and allowed to set, to form the anti-slip-coated male mould. The mixture may be applied by hand or by mechanical means. Suitable means of applying the anti-slip mixture include rolling, spraying, painting or any combination of these. For example the anti-slip mixture may be applied by hand using a roller or mini-roller, such as a wool roller.

The anti-slip mixture may be applied as a single layer or as multiple layers. Preferably the anti-slip mixture is applied to give a total thickness in the range from 0.1 mm to 50 mm, preferably 0.5 mm to 20 mm, such as 1mm to 10 mm.

Typically the anti-slip mixture is applied at a rate of 1 kg to cover 84 m^.

The anti-slip mixture is allowed to set, prior to use of the anti-slip-coated male master mould in the formation of the first female mould. This requires the resin (component (b)) to harden or cure. Preferably the anti-slip mixture is allowed to set to a hardness index of at least 35 on the Barcol Hardness scale (ASTM D2583, Model 934-1) before use in forming the female mould. More preferably the mixture is allowed to set to a hardness index of at least 40, for example at least 44.

Typically the anti-slip mixture will set in air at room temperature over a period of between 10-24 hours, for example 14-16 hours. It may be preferable to accelerate the hardening of resin in the anti-slip mixture by the application of heat or use of an inert atmosphere, or both. Heating to a temperature in the range from 70 to 120°C may accelerate hardening to take from 20 to 120 minutes. Preferably, if heat is applied to accelerate cure it will be in air and in a temperature range from 80 to 110°C, for example 90 °C or 100 °C, most preferably 90 °C.

Typically, once the anti-slip mixture has set, the anti-slip-coated male master mould is treated with a mould-release agent, for example in 1-12 treatments. Generally the mould-release agent is applied in multiple treatments, for example 2-8, such as 6 treatments. Mould-release treatment allows the anti-slip coated male master mould to be separated more easily from the female mould, minimising or eliminating separation damage to either mould, for example due to surface adhesion. Use of a mould-release agent for this purpose is standard in the field and various suitable reagents are available. For example, the Chemlease® PMR family, such as Chemlease® PMR-09-EZ or similar agents, may typically be used.

Anti-slip female mould

The female moulds produced according to the process of the invention may be produced from the anti-slip-coated male master mould using standard techniques known in the field. The female moulds produced are anti-slip female moulds, i.e. have an indented surface structure integrated into the mould which provides superior anti-slip properties in the articles produced therefrom.

The female mould according to the process of the invention typically has a multilayer structure, i.e. comprises multiple layers. The female mould may be formed by applying individual layers of materials to the anti-slip-coated male master mould. Typically the female mould comprises at least one gel-coat layer, at least one layer comprising fibre-glass matting and a bisphenol resin, at least one layer comprising a polyester resin, and at least one layer comprising plywood.

Typically, the female mould comprises two layers of gel coat. It is preferred that the gel coat comprises or consists of a vinylester resin. For example GM Norpol 9000H black or GM 60014 Green gel coat.

The fibre-glass and bisphenol resin layer typically comprises MC450-960 fibre-glass matting and a bisphenol A vinyl ester urethane resin, such as ATLAC 580ACT resin. Preferably the female mould comprises at least two successive layers of the fibre-glass and bisphenol resin layer, for example three layers.

The layer comprising a polyester resin may optionally further comprise a catalyst. Preferably this layer comprises a low styrene emission, orthophthalic-based unsaturated polyester resin and a peroxide catalyst. Suitable resins include SYNOLITE® 6060-P-1, for example. Preferably this layer follows a fibre-glass and bisphenol layer. Preferably the female mould comprises at least two successive layers of the layer comprising a polyester resin.

The layer comprising plywood preferably comprises % inch (1.27 cm) plywood and a bonding paste such as BLIFA 740-1440 paste mixed with 2% peroxide catalyst. Preferably this layer follows the layer comprising a polyester resin and is followed by a further layer comprising polyester resin.

Preferably the female mould comprises at least two successive gel coat layers followed by at least three successive fibre-glass and bisphenol resin layers. More preferably this is followed by at least two successive layers comprising a polyester resin as defined above, followed by at least one layer comprising plywood, and at least two subsequent successive layers comprising a polyester resin.

Preferably each layer that comprises a resin is allowed to set to a hardness index of at least 35 on the Barcol Hardness scale (ASTM D2583, Model 934-1) before the application of the next layer. More preferably each layer is allowed to set to a hardness index of at least 40, for example at least 44 before application of the next layer.

After the final layer has set to the desired hardness the female mould may be separated from the anti-slip-coated male master mould using standard separation techniques. The female mould typically may be separated from the anti-slip-coated male master mould after a period of approximately 1 day, for example 10-36 hours, preferably 20-30 hours, more preferably 24 hours.

The female mould may be cleaned, for example with acetone, before use.

Typically, the female mould may be treated with a mould-release agent before use, for example in 1-12 treatments. Generally the mould-release agent is applied in multiple treatments, for example 2-8 treatments, such as 6 treatments. Mould-release treatment allows the female mould to be separated more easily from the cast article or the further male mould being produced therefrom, minimising or eliminating separation damage to either, for example due to surface adhesion. Use of a mould-release agent for this purpose is standard in the art and various suitable reagents are available. For example, the Chemlease® PMR family, such as Chemlease® PMR-09-EZ or similar agents, may typically be used.

Optionally the female mould may be used to produce a new male master mould, using standard techniques known in the art.

Articles

The anti-slip article of the invention may be produced from the female mould using standard industry casting methods.

Typically, the article comprises at least one layer of gel coat. It is preferred that the gel coat comprises or consists of a vinylester resin. For example GM Norpol 9000H black or GM 60014 Green gel coat.

The at least one gel coat layer may be applied to the female mould first. Typically the at least one gel coat layer may be applied by spray-coating, but any suitable application process may be used. For instance, rolling, spraying, painting, or any combination thereof.

The gel coat layer may be allowed to harden to a hardness index of at least 40, for example at least 44, on the Barcol Hardness scale. Preferably hardening may be accelerated by baking. For example, baking at approximately 40 °C for up to 20 minutes.

Once the gel coat layer has hardened, a stone resin mixture is poured into the female mould and distributed approximately evenly around it.

The stone resin mixture may comprise a mixture of crushed material and resin. Suitable crushed material may comprise or consist of crushed stone such as limestone or dolomite, and/or crushed stone substitutes such as sand, gravel, iron and steel slag, sintered or expanded clay or shale, perlite or vermiculite, or any combination thereof. Preferably the crushed material comprises or consists of crushed stone, especially crushed limestone.

The resin in the stone resin mixture preferably comprises a low styrene emission, orthophthalic-based unsaturated polyester resin. For example, PALATAL® U 541 TV-05, PALATAL® U 541 TV-11, PALATAL® U 570 TV-04, PALATAL® U 569 TV-03, SYNOLITE® 6060-P-1, SYNOLITE® 2020-P-1, ATLAC 580 ACT, or mixtures thereof.

The stone resin mixture optionally and preferably further comprises a catalyst. Preferably this mixture comprises a peroxide catalyst such as a 2% peroxide catalyst.

In a preferred embodiment applicable to all aspects of the invention the stone resin mixture may comprise crushed limestone, SYNOLITE® 6060-P-1 and a 2% peroxide catalyst.

Preferably the stone resin mixture is allowed to set to a hardness index of at least 35 on the Barcol Hardness scale (ASTM D2583, Model 934-1) before the article is separated from the female mould. More preferably the mixture is allowed to set to a hardness index of at least 40, for example at least 44 before article is separated from the female mould.

The article is separated from the mould using standard techniques known in the art.

The process of the invention described herein provides articles such as drain bases having a separate or integrated drain aperture. Preferably the articles comprise or consist of a drain base having an integrated drain aperture, such as a bathtub or shower tray.

More preferably the articles comprise or consist of a shower tray, i.e. a drain base suitable for use in a shower, providing enough structural strength to support the weight of users and also providing a configuration suitable for drainage of water to a separate or integrated drain aperture. Most preferred articles are shower trays having an integrated drain aperture.

Anti-slip performance

Assessing the slip-resistance of flooring uses methodology that is based on using a pendulum in the pendulum coefficient of friction (CoF) test. The pendulum CoF test (also known as the portable skid resistance tester, the British pendulum, and the TRRL pendulum) is the subject of a British Standard, BS 7976: Parts 1-3, 2002.

The method is based on a swinging, imitation heel (using a standardised rubber soling sample), which sweeps over a set area of flooring in a controlled manner.

The slipperiness of the flooring has a direct and measurable effect on the pendulum test value (PTV) given. The preparation of the standard rubber sliders is detailed in BS 7976: Parts1-3, 2002 and the UK Slip Resistance Group (UKSRG) guidelines.

This test is used in the industry to assess the anti-slip performance of anti-slip articles such as shower trays, bathtubs, wet room flooring and so on. Pendulum results should be interpreted using the information reproduced in Table 1 (from UKSRG, 2011).

Table 1

Articles produced according to the process described herein typically demonstrate pendulum test values of at least 40. Preferably this is at least 45, more preferably at least 47. Most preferably articles produced according to the invention demonstrate this performance under wet conditions.

In particular shower trays produced by the process described herein typically provide pendulum test values of at least 45, preferably at least 47.

Figures

Figure 1 - line drawing of typical female mould according to the invention.

Figure 2 - perspective view of a typical article produced by the process

Figure 3 - cross-section view of typical article produced by the process, as shown in figure 2.

Figure 1 shows the layers of a typical female mould according to the invention. The layers are numbered 1-8, each number corresponding to a different layer as follows: 1 - GM Norpol 9000H Black or GM 60014H Green Gel coat 2 - GM Norpol 9000H Black or GM 60014H Green Gel coat 3 - MC450-960, 900gms fibre glass matting mixed with Atlac 580ACT resin and 2% peroxide catalyst 4 - MC450-960, 900gms fibre glass matting mixed with Atlac 580ACT resin and 2% peroxide catalyst 5 - MC450-960, 900gms fibre glass matting mixed with Synolite 6061-P-1 resin and 2% peroxide catalyst 6 - MC450-960, 900gms fibre glass matting mixed with Synolite 6061-P-1 resin and 2% peroxide catalyst 7 -1/2 inch plywood attached using 740-4410 binding paste mixed with 2% peroxide catalyst 8 - MC450-960, 900gms fibre glass matting mixed with Synolite 6061-P-1 resin and 2% peroxide catalyst

Examples

Example 1: Procedure for producing an anti-slip female mould.

[1] A standard master “male” mould is selected in the size and shape required.

[2] lOOgms of Synolite resin is measured out. Into this is mixed 20gms of fine particulate, 2gms of medium particulate. The particulate consists of crushed natural tree nut by-products with fine being between 0.0103 - 0.033 inches (261-838 pm) in size and medium being between 0.033 - 0.049 inches (838-1244 pm) in size. The mixture is carefully combined to ensure an even concentration of the particulate throughout resin. Then 2% peroxide catalyst is added to ensure a 20 minute working time.

[3] The mixture is then added evenly onto the surface of the mould using a mini lamb’s wool roller to ensure an even spread across the entire surface.

[4] The mould is then left for 15 hours to allow the resin to harden.

[5] This mould is then treated with release agent PMR-90-EZ.

[6] Step [5] is then repeated several times (on average 6) until the mould surface is ready.

[7] The mould is then covered with GM Norpol 9000H Black or GM 60014H Green Gel coat which is allowed to harden.

[8] Step [7] is then repeated.

[9] The mould is then covered with a layer of MC450 - 960, 900gms fibre glass matting that is mixed with a combination of Atlac 580ACT resin and 2% peroxide catalyst. The mould is allowed to harden [10] Step [9] is then repeated.

[11] Step [9] is then repeated.

[12] The mould is then covered with a mixture of Synolite 6061-P-1 resin and 2% peroxide catalyst. The resin is allowed to harden.

[13] Step [12] is then repeated.

[14] The mould is then encased in 'A inch plywood that is attached to it using 740 -4410 binding paste mixed with 2% peroxide catalyst. This is allowed to set.

[15] The mould is then covered with a mixture of Synolite 6061-P-1 resin and 2% peroxide catalyst. The resin is allowed to harden.

[16] Step [15] is then repeated.

[17] After a day the “female” mould is then separated from the male master mould from which shower trays can be cast using standard industry casting processes.

Example 2: Testing for anti-slip performance

Coefficient of dynamic friction measurement was carried out in accordance with BS 7976-2 and the UKSRG Guidelines 2011. These industry standard methods of testing are essentially the same but with a slight difference between the two methods of preparation of the rubber sliders. Testing has been carried out in accordance with the UKSRG Guidelines 2011 as both the HSE and UKSRG agree that this is best practice. A prepared standard rubber slider attached to a weighted 'shoe' is allowed to swing from a horizontal point of release. The slider is mounted on a spring loaded bracket and makes contact with the floor for a known distance, applying a calibrated force. The height to which the shoe travels after contacting the floor gives a reading of the Pendulum Test Value (PTV, formally known as SRV Slip Resistance Value).

Test surfaces are subject to eight measurements of the PTV with the first three being discounted from calculations of the median. Tests are carried out in the principal direction, at 45° to the principal direction and at 90° to the principal direction. Each direction is tested under both wet and dry conditions, totalling 48 measurements. A median value is generated for wet and dry tests based on the performance in different directions, though consideration should be given to surfaces with a directional finish.

Slip potential can be classified based on PTV:

12 test surfaces were prepared and tested for anti-slip performance according to BS-7976-2 as described above.

The results are shown below:

Claims

1. A process for manufacturing an anti-slip article comprising: (i) applying an anti-slip mixture to the surface of a male master mould; (ii) allowing said anti-slip mixture to set, to provide an anti-slip-coated male master mould; (iii) making a female mould from the said anti-slip-coated male master mould; (iv) producing said anti-slip article from said female mould; wherein said anti-slip mixture comprises: (a) at least two particulate materials, including a first particulate material, A1, having a first mean particle size, P1, and a second particulate material, A2, having a second mean particle size, P2, wherein A1 and A2 may be the same or different, and wherein P2 is greater than P1; (b) at least one resin; and (c) a catalyst or curing agent.

2. The process as claimed in claim 1 wherein said anti-slip article comprises or consists of a drain base having an integrated drain aperture, preferably wherein said anti-slip article comprises or consists of a shower tray.

3. The process as claimed in claim 1 or claim 2 wherein A1 is selected from the group consisting of natural sand, artificial sand, crushed stone sand, crushed gravel sand, crushed tree-nut by-products or mixtures thereof.

4. The process as claimed in any preceding claim wherein A2 is selected from the group consisting of natural sand, artificial sand, crushed gravel, crushed stone, partially crushed gravel or stone, crushed tree-nut by-products, or mixtures thereof.

5. The process as claimed in any preceding claim wherein the particles in A1 and A2 have a shape that is substantially spherical, ellipsoid, droplet or bean shaped, preferably wherein at least 95% of the particles are substantially spherical.

6. The process as claimed in any preceding claim wherein the first mean particle size, P1, falls within the range from 200 to 850 pm and the second mean particle size P2 falls within the range from 800 to 1300 pm.

7. The process as claimed in any preceding claim wherein the mean particle size differential, P1:P2, is in the range from 10:11 to 10:65.

8. The process as claimed in any preceding claim wherein the mean particle size is the volume-average mean particle size measured by light scattering, preferably using a Coulter LS 230 Laser Light Scattering Particle Sizer.

9. The process as claimed in any preceding claim wherein the particle size distribution of A1 is in the range of 200 to 850 pm, and the particle size distribution of A2 is in the range of 800 to 1300 pm.

10. The process as claimed in any preceding claim wherein A1 and A2 are both crushed tree-nut by-products, the particle size distribution of A1 is in the range 260-840 pm and the particle size distribution of A2 is in the range 840-1250 pm.

11. The process as claimed in any preceding claim wherein the said anti-slip mixture comprises 5-35% particulate materials as a percentage by total weight of components (a) and (b).

12. The process as claimed in any preceding claim wherein the weight ratio of A1 to A2 in the anti-slip mixture is in the range from 4:1 to 16:1 by weight.

13. The process as claimed in any preceding claim wherein the anti-slip mixture comprises 0.5-5% of the second particulate material A2, as a percentage by total weight of components (a) and (b).

14. The process as claimed in any preceding claim wherein the said at least one resin is a polyester resin, preferably an orthophthalic based unsaturated polyester resin.

15. The process as claimed in any preceding claim wherein the anti-slip mixture comprises 65-95% of the said at least one resin as a percentage by total weight of components (a) and (b).

16. The process as claimed in any preceding claim wherein the said catalyst or curing agent is a 2% peroxide catalyst.

17. The process as claimed in any preceding claim wherein the said anti-slip mixture further comprises 1-20% of at least one filler, by super-addition.

18. The process as claimed in any of claims 1-16 wherein the said anti-slip mixture consists of the said two particulate materials A1 and A2, the said resin, and the said catalyst or curing agent.

19. The process as claimed in any preceding claim wherein the said anti-slip mixture is applied to the surface of said male master mould by rolling, painting, spraying or any combination thereof.

20. The process as claimed in any preceding claim wherein the said anti-slip mixture is applied to a total thickness in the range from 0.1 to 10 mm, preferably 0.1 to 5 mm.

21. The process as claimed in any preceding claim wherein the said anti-slip mixture is allowed to set to a hardness index of at least 35 on the Barcol hardness scale (ASTM D2583, Model 934-1) before the anti-slip-coated male master mould is used in making the female mould.

22. The process as claimed in any preceding claim wherein the said anti-slip-coated male mould, once set, is treated with from 1 to 12 treatments of a mould-release agent, before making the female mould.

23. The process as claimed in any preceding claim wherein the said female mould has a multi-layered structure comprising at least one gel coat layer, preferably said gel coat layer comprising a vinylester resin.

24. The process as claimed in any preceding claim wherein producing the said antislip article from the said female mould comprises applying a gel coat layer and allowing said layer to set to a hardness index of at least 35 on the Barcol hardness scale (ASTM D2583, Model 934-1).

25. The process as claimed in claim 24 wherein producing the said anti-slip article further comprises subsequently pouring into said female mould a stone resin mixture comprising a mixture of crushed material, resin and preferably a catalyst.

26. An anti-slip article obtained by the process according to any preceding claim.

27. The anti-slip article according to claim 26, said article comprising or consisting of a drain base having an integrated drain aperture.

28. The anti-slip article according to claim 26 or claim 27, said article comprising or consisting of a shower tray.

29. Use of an anti-slip mixture comprising: (a) at least two particulate materials, including a first particulate material, A1, having a first mean particle size, PI, and a second particulate material, A2, having a second mean particle size, P2, wherein A1 and A2 may be the same or different, and wherein P2 is greater than PI; (b) a resin; and (c) a catalyst or curing agent in the manufacture of an article having anti-slip performance of at least 40, preferably at least 45, more preferably at least 47, as measured according to the British standard anti-slip test, BS-7976-2.

30. The use as claimed in claim 29 wherein said article comprises or consists of a drain base having an integrated drain aperture, preferably wherein said article comprises or consists of a shower tray.

31. The use as claimed in claim 29 or 30 wherein performance as measured according to BS-7976-2 is measured under wet conditions.

32. The use as claimed in claim 29, claim 30 or claim 31 comprising a process as defined in any of claims 1 to 25.