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Development of safe and resilient flooring with controlled slip under varying environments

Final Report Summary - SLIPSAFE (Development of safe and resilient flooring with controlled slip under varying environments)

Executive Summary:
The production and installation of resilient flooring in public and private buildings is a major business in Europe involving various sectors including material and coating production, designers, architects, installers, cleaners as well as the end-users. The main requirements are: durability, ease of installation, optical appearance, ease of cleaning and low cost maintenance.

On the other hand slip accidents are a major source of injury in Europe. The floorings industry is therefore challenged to develop flooring with improved slip behaviour under varying environmental conditions (humidity caused by rain or cleaning can reduce friction dramatically). Besides there is often a conflict of interest between decreasing slipperiness and maintaining ease of cleaning because conventional approaches to reduce slipperiness imply the macroscopic roughening of the surface resulting in the collection of dirt (problem in hospitals).

With new standards and testing methods harmonised in Europe this problem becomes more prominent, requiring substantially new and innovative approaches to address the problem by the flooring industry, like material suppliers, coating technology manufacturers, flooring installers, cleaners and companies developing testing methods.

Therefore the SlipSafe project has involved the key players of the industry in an integrated bottom-up project in order to find the best solutions to the issues above mentioned. The key objectives defined at the beginning of the project were to improve slip resistance on wet PVC floors, improve the service life and allow easy cleaning.

The focus here was not to develop new antislip floor which already exist especially for industrial application but well to make “regular” floor less splippery in wet conditions.

The project goals have been investigated by several technological approaches taking into account new material developments, processes and testing methods.

The first phase of the project was focused on new intelligent material formulations and processes to gain control of the interface between flooring and shoe. These new formulations were used in the studies of the tribological phenomena of slip resistance under varying environmental conditions.

Then the search of new technologies, such as the ultrasonic coating technology, has enabled the use of various particles in the after-treatment process to renew existing or worn out floorings with anti-slip properties.

Another relevant outcome achieved in the project is the development of a new testing method, allowing monitoring of slipperiness as a function of the wear of installed flooring material faster and cheaper than with existing methods. Also a mobile testing device has been developed which includes the improvements and innovations in the testing methods identified in the project. It is lighter, ease of use and usable of small testing areas.

Also several case studies and the industrial scale up have shown the potential of the new flooring formulations, coatings and surface treatment processes to obtain slip resistance properties in different scenarios. Finally a Life Cycle Assessment has proved that the Slipsafe approach contributes to have competitive and environmental friendly new flooring solutions.

Project Context and Objectives:
1. Summary description of Processing and development of surface treatment process
Work package 3 of the Slipsafe project aimed at developing new or improved processing technologies for the base material to be able to incorporate slip-reducing material formulations in industrial flooring manufacturing processes and to fully reveal the new potential of the anti-slip materials developed. Another aim was a new surface treatment process for the targeted surface modification of new and worn-out floorings.
1.1 The modification of new PVC floors with non-slip properties:
Task 3.1 included the optimization of the coating system by the investigation of the system parameters:
• Coating tests with functional particles.
• Examination of the coating process and the influence on the sliding properties.
• Sample production for the characterization of slip properties and the long-term behavior of the modification.
1.2: The refurbishment of installed PVC floors to improve the slipping properties:
In task 3.2 the results obtained in task 3.1 were used for refurbishment to modify the structure of the coating system and increase the slip resistance of already installed floors.
Ultrasound: Ultrasound waves are allocated above the acoustic range, between 20 kHz and 1 GHz. They are propagated in longitudinal and transversal waves, with intensities of up to several kW/cm². Ultrasound-assisted processes are mainly influenced by the amplitude and frequency of the ultrasound, pressure and temperature in the process and by material parameters. Ultrasonic energy is widely used in cleaning processes, drilling, welding, medicine technology, sensor technology and electronics.
Ultrasonic for surface coating: Fraunhofer ICT developed (previously to the project) an ultrasound system for the surface modification of polymers, which formed a basis for work in SlipSafe. The coating system can be used to incorporate particles into polymeric matrices. This process results in highly flexible processing for polymeric surface treatment. The particles are supplied as a suspension avoiding dust causing health and safety problems. They do not have to be dispersed in this carrier, as they are dispersed by the process itself during incorporation into the polymeric matrix by the ultrasonic energy. The functionalized particles are only embedded in the upper layer, ensuring the functionality where needed and saving costly particles. The method can also be used for semi-finished products like profiles coming from the extrusion as well as for end-user parts. The use of ultrasound on even surfaces like foils or plates is possible by using rolls or sliding rails as ultrasonic sonotrodes for the energy transfer.
Based on this technology, a new processing technology for the treatment of soft PVC floor coverings was developed within the SlipSafe project.
Stationary device
The existing ultrasound system at Fraunhofer ICT was modified for the new application in the Slipsafe project. For this purpose, a frame structure was selected with profiles that can be easily modified and rebuilt. The device is designed as a laboratory system for the coating of PVC panels and tiles with particles. The system allows all the parameter tests to be performed with different ultrasound components, without a major redesign of the structure. Furthermore, a transport system for the samples and a pump system for the suspension of the particles is integrated into the system.
Mobile device
With the findings of the parametric studies, modifications were made to the frame of the ultrasonic laboratory system, aiming at building a prototype system for a mobile ultrasound device for the treatment of already installed floorings.
This prototype system will serve as a demonstrator to show that the re-coating of worn-out PVC floors is possible using a mobile system on an already installed floors.

2. Summary description of application development and case studies
From the beginning of the SlipSafe project, the RTD performers either have developed several new recipes for PVC compounds (dry blend and plastisol) or have applied an ultrasonic surface treatment both to be used for slip improved PVC floor coverings. Based on this experimental work the RTD performers selected together with ERFMI the most promising samples (one for ultrasonic treatment, two for plastisol and two for dry blend) for the pre industrial tests.

The floorings involved in this study are the prototypes selected and manufactured by the flooring materials developers in the SlipSafe project. In all the cases, the materials are PVC based. Samples were DIN A4 size. All the samples excepting the reference material were sanded to reproduce the type of surface of industrially developed floor and initial wear. Fraunhofer ICT and AIMPLAS produced 4 m2 of each of the samples for the case studies and the product testing.

ERFMI executed in the laboratories of two different members of the Industry Reference Group (IRG) the initial product testing of the selected samples according to a list of requirements and test methods for the initial testing round and validation of typical flooring products. Samples for case studies were installed in different, controlled environments at AIMPLAS, Fraunhofer ICT, Smithers Rapra and IK4 - Tekniker.

An installation of floor covering samples at the ERFMI office in Brussels, which was originally only foreseen for demonstration during the SlipSafe meeting held on the 13th and 14th April 2016, was left in place for a further case study.

3. Summary description of environmental and economic studies

The SlipSafe flooring system was analysed through an eco-efficiency study, economic analysis and legislation review to guarantee that the new products are cost competitive, environmental friendly and fulfil all related legislation. The main objectives in WP8 are detailed below:
• Collecting information on economic and environmental data on new SlipSafe flooring and processes (manufacturing process, type of products, selected formulations and materials with respect to production price, output capacity, life-cycle of product etc.).
• Evaluation of selected data and performing deep economic study on the new flooring system to evaluate economic viability of the project results, detailed analysis for new materials and production processes with respect to commercial floorings, preparation of business plan.
• Collection and review of environmental data on new PVC floorings
• Preparing and submitting the deliverables: D8.2: Life Cycle Assessment Report and D8.3: Final viability and business plan.

Project Results:
1. Work and results in Processing and development of surface treatment process
Approach: The basic idea of this approach was to integrate warning signs into the flooring, which are activated by wetness, warning people of wet and slippery areas on the PVC floor after cleaning. The processes needed to be reversible.
Results: As a result of the project it became clear that optical warning signs on the floor can be realized by locally applied ultrasonic coatings with pH-indicators in the surface of PVC-floors, which react to a change in the pH-value of the wetting liquid. Unfortunately it was not possible to detect pH-neutral water directly with the selected color indicators. Further work is needed to improve the long-term stability of the color change particles. Due to the thin coating layer and the washing-out of the color indicator the effect faded out after multiple cleaning processes.
Approach: Two different effects were studied to increase the slip resistance of PVC floors in wet conditions: (1) Water absorbing particles used to reduce the water film on the PVC floor and (2) Incorporated particles swell when in contact with water and thus change the surface structure of the floor in order to increase the friction value.
Results: Tests with different water-absorbing particles were carried out. The incorporation of the un-swollen particles via US technology was in general successful. Unfortunately after swelling of the particles, the particles mostly detached from the surface of the PVC sample so that the effect was quickly lost. The only relevant influences on the slip properties was measurable before the swelling: the hard particles increased the friction properties of the flooring surface in dry conditions.
Approach: Modification of the surface structure of the PVC floor by incorporating hard particles in order to increase the slip-resistance.
Results: The studies clearly indicate that hard particle can significantly increase the slip resistance of PVC floors as long as they exceed a minimum particle size. This tendency could be reproduced with different particles.
Approach: The idea behind this test is to study the long-term behaviour of different surface modifications under wear conditions. The examination of the long-term properties of the ultrasound coating was carried out by IK4-TEKNIKER. The selected machine is often referred to as a scrub, abrasion and wash ability tester. It is designed to provide an accelerated method to determine the wear resistance of surface coatings, and also to test the performance of cleaning compounds. Before and after the abrasion test the PTV and the mass of the samples were measured.
Results: After carrying out the long-term test, it was found that the particles used showed only a minimal tendency to wear in this configuration.
Approach: The aim of this study was the long-term investigation of the coated PVC floor in real environments. The WP3 samples T42CS were installed in the different test areas provided by the project partners. The installed samples were regularly tested and the Pendulum test Value (PTV) results were measured over a period of 6 months. Furthermore all the installed samples were ultimately analyzed according to industrial standards
Results: The ultrasonic coated samples T42CS showed comparably stable results over the course of the case study.

2. Work and results in the development of testing methodologies for characterizing flooring slip and wear resistances
SlipSafe project has ended with the development of four new testing methodologies to characterize the slip resistance and durability of PVC floorings. For each one the testing conditions and needed materials were defined in detail.
Protocol 1 for characterizing slip resistance of floorings in wet conditions:
The Protocol 1 measures the friction coefficient of floors with water as contaminant agent. The testing method is very versatile in terms of working conditions (speed, load, temperature, etc.).

Protocol 2 for characterizing slip resistance of floorings in dry conditions:
In this case tests are performed without any contaminant. An important difference with protocol 1 is that a linear reciprocating movement is used during the test. This methodology has the same advantages as Protocol 1.

Protocol 3 for characterizing slip resistance and durability of floorings in wet conditions:
A new approach was proposed with this testing methodology since it provides information about the variation of slip resistance of flooring caused by surface ageing, in particular, ageing because of flooring wear. Friction and wear measurements are performed using several devices and obtained results are compiled to obtain information about flooring durability and its ability to keep the original slip resistance levels. This is a very interesting information since it can be used to develop higher quality floorings that ensures a longer life.
The main idea of this testing methodology is based in measuring the slip resistance of a PVC flooring before and after being exposed to a wearing process. The possible variation in slip resistance would give an idea about the variation of slipperiness level. Also, complimentary measurements (roughness and mass variation) are carried out to characterize the wear process.
The test is divided in 3 phases:
1. Initial situation (before wearing process): Slip resistance, mass and roughness measurements.
2. Wear process: surface wear evaluation with the washability test.
3. Final situation (after wearing process): mass, roughness and slip resistance measurements.
The validation of the test protocol was based in the testing of four materials with already known performance in terms of slip resistance durability.
A big number of tests have been performed in order to investigate the friction and/or wear resistance of PVC floorings. These characteristics have been tested using different testing apparatus and methodologies, using both new developed protocols and standard tests. Test results have supported material developer partners to optimize flooring formulations. Tests were carried out in wet and dry conditions and using different types of counter materials.
The following general conclusions can be made:
(A)Dry friction: friction strongly depends on the counter material, that is, on the slider material.
(B)Wet friction: for the group of materials tested, the linear prediction of measured CoF related to the PTV value.
(C)Slip and wear durability resistance: in new condition, studied coatings, fillers and sanding increased the flooring resistance of the base material. After the wear process, sanded and filled materials were more durable in terms of keeping the original slip levels. Finally, the study of the influencing parameters in the coating process revealed that process temperature had an effect in the slip resistance after the wear process and that process temperature and process had an effect in the wear resistance of the floorings.
(D) Slip resistance (GMG test): as observed in tests with other testing methodologies it was conformed that friction with SBR was noticeably lower than with Slider 96. Also it was observed the important reduction of friction when adding NaDS to DI water. In addition, a lack of correlation between pendulum and GMG results was observed in wet conditions, but correlation was better when using SBR (standard GMG slider) than Slider 96 (pendulum slider).
Additionally, based on Protocol 1 developed by IK4-TEKNIKER, GTE constructed a new portable device to measure the coefficient of friction of floorings based on a rotating movement. It was shown that the new device gave the same results as the standardized reference device GMG200 with linear movement. Some characteristics of this device are that it needs less testing area, is lighter and has easier handling.

A complimentary characterization (roughness, wettability, hardness, surface appearance, surface resistivity) of studied PVC floorings materials and paints has been performed. This characterization has been carried out using different test apparatus and methodologies, using standard and non-standard tests.
Individual studies were performed to investigate the effect of different parameters in the studied material characteristics.
IK4-TEKNIKER has participated in all the meetings organized by the AENOR Technical Committee of Standardization AEN/CTN 41/SC 11, the Spanish national group that covers activities related to Slip Resistance and that follows the activity of the European CEN/TC 339 Slip resistance of pedestrian surfaces - Methods of evaluation. IK4-TEKNIKER has also participated in the meetings organized by the European CEN committee. The main activities developed in the SlipSafe project has been disseminated in CENT/TC 339 in order to develop a new standard on flooring slip resistance.

3 Work and results in technology validation at laboratory scale
The novel flooring materials, surface modified and after-treated flooring materials produced during WP2 and WP3 were characterised by Smithers Rapra using the pendulum test.

This test, particularly in wet conditions, is an efficient way to simulate the slip conditions that occurred when a pedestrian heel strikes a wet floor. The pendulum tests were performed in accordance with the European and British Standards EN 13036-4, BS 7976-1 and the UKSRG guidelines issue 4. Slider 96 was used, and testing was carried out in both dry and wet conditions.
The initial samples did not exhibit conclusive anti-slip properties. Several actions were investigated to remedy the low PTVs obtained such as studying new inorganic particles, different filler contents and combinations and adding a roughness to the surface. The surface texture was modified by using either an embossed mould or by sanding the samples. In WP3, an Ultrasonic (US) coating system was used by ICT to modify the surface of flooring materials. Several types of inorganic particles of different natures and sizes were coated on base PVC materials. The initial samples developed in WP3 by coating various particles did not exhibit conclusive anti-slip properties. The main problem was thought to be that in wet conditions the particles were preventing the water from flowing, forming a water-film that affected the measurements. Several actions were investigated to remedy the low PTVs obtained such as studying water absorbing particles and adding a surface structure i.e. a surface roughness or a hydrophilic/hydrophobic surface. The surface structure was modified by using either a mechanical process or a plasma treatment. Creating a hydrophilic/hydrophobic surface by modifying the energy surface of PVC flooring also proved to efficiently improve the anti-slip properties.
The evaluation of the slip resistance of all the materials produced during WP2 and WP3 enabled us to identify the most promising flooring materials in terms of anti-slip properties. These samples were further evaluated through case studies and were installed in different, controlled environments at the premises of the RTD partners AIMPLAS, Fraunhofer ICT, IK4 – Tekniker and Smithers Rapra. At Smithers Rapra, the samples were temporary glued in a laboratory external entrance area with medium pedestrian traffic, wet and dirt from outside and possible sack truck traffic.
The slip resistance of the case study materials was characterized with the pendulum test as a function of the time. After 6 months of pedestrian traffic and cleaning actions the case study flooring materials showed a better slip resistance than the reference commercial flooring especially in wet conditions.
Some candidate flooring materials selected from the flooring materials produced during WP2 and WP3, and also during the pilot campaign carried out in December 2016, were characterised by Smithers Rapra with the ramp test.
Additionally, pendulum tests and roughness measurements were performed in-situ by Smithers Rapra at TBA facilities for different coatings applied directly onto the floor of the warehouse. The pendulum tests were also performed in accordance with the European and British Standards EN 13036-4, BS 7976-1 and the UKSRG guidelines issue 4. Three painted areas with different traffic (Area1In both dry and wet conditions and for the 3 areas, the surfaces S2 and S4 exhibited the best PTVs. For all formulations, in a first step the PTVs quickly decreased (from September to October) but then increased again. The wearing out of materials had a steep negative effect in the first instance but exhibited afterwards a positive effect in the long term. Area3 could be seen as an accelerated ageing area in comparison to Area1. S2 and S4 which exhibited the best PTVs. For almost all formulations, the roughness slightly decreased over time.
New coatings developed by TBA were applied onto PVC based materials and were also tested with the pendulum by Smithers Rapra.
The coating P07+coulour change exhibited the most interesting slip resistance with PTVs around 45 in wet conditions.

4 Work and results in Industrial scale-up
The RTD performers have selected together with ERFMI the most promising additives (one each for plastisol, and dry blend) for the pilot tests. Fraunhofer ICT and AIMPLAS sent these additives to the IRG partners involved.
ERFMI was involved in the pilot production and first initial product testing of the produced samples according to the selected list of requirements and test methods for the initial testing round in these two locations.
Further the optimized ‘candidate’ floor covering test materials from dry-blend were analysed according to the German DIN ramp test and the durability of the plastisol test material was evaluated with the PEDATRON™ test.

5 Work and results in Environmental and Economic Studies
The SlipSafe flooring system was analysed through an eco-efficiency study and economic analysis to guarantee that the new product is cost competitive and environmental friendly and fulfil all related legislation. An early economic evaluation was performed already in the first period and showed that the new flooring is economically viable. The resulting economic viability report was taken into account as one of the mid-term review criteria. In the second period a deep economic study was performed to evaluate the economic viability of the project results, by evaluation of data gathered throughout the project’s life and from all project partners. This economic viability report with business plan was the base for the Exploitation Plan. Input for WP8 based on data gathered from all partners and results in the WP1, WP2 and WP3 (specifications of materials and technologies, selected formulations, outputs, prices of materials etc.). Tasks within work package 8 consisted of:
Task 8.1 Life Cycle Assessment (LCA): with an LCA analysis we studied the environmental impact of the SlipSafe flooring materials. Life Cycle Assessment was carried out following the standard ISO 14040. ERFMI already has prepared an LCA approach for currently used PVC floorings. Comparison of the new materials with the currently used ones was carried out during this task. This LCA has shown that the type of PVC and fillers used in the formulations can have an impact on the environment.
Task 8.2 Economic analysis: an early economic evaluation was performed already in the first period of the project and defined the economic viability of the new system. A deep economic study was performed to evaluate the economic viability of the project results, by evaluation of data gathered throughout the project’s life. This economic viability report was the base for the Exploitation Plan. The results of analysis foresee a positive scenario for the SlipSafe flooring commercialization in the coming years, in terms of the PVC to be used as a base material and in terms of the potential sales in SlipSafe flooring made by new material.
Task 8.3 Business plan, described in D8.3 helped partners to decide on exploitation strategy.
Work Package 8 was completed in the second reporting period and two deliverables have been completed and submitted. D8.2 (Life Cycle Assessment report) and D8.3 (Final viability and business plan) were submitted in February 2017.

Potential Impact:
• Development of various approaches and technologies to improve the safety of PVC floors in wet conditions.
• Realization of a prototype system with optimized parameter configurations for the ultrasonic coating of PVC floors.
• Generating results and knowledge for the companies and organizations of the project which can contribute to an increase in the slip safety of PVC floors.

• Important contributions towards the development of the new standards in the field of slip resistance.
• Development of new user-friendly testing devices for determining flooring slip resistance.
• Results, knowledge and device developments for providing a number of benefits to companies and organisations that are involved with the testing of flooring slip behaviour, both from a research and development perspective and the provision of a testing service for quality control work.
• This fact will have a direct impact on the improvement of the security of pedestrians in relation to the decrease of injuries by slips.

• There are promising developments within the SlipSafe project. The lab testing showed that the samples produced could by applied as a floor covering, but also further improvements amongst others in scratch resistance and lightfastness have to be achieved. In the case studies, interesting improvements of slip properties could be observed.

• The evaluation of the slip resistance, in particular with the pendulum test, of all the novel flooring materials, surface modified and after-treated flooring materials produced during WP2 and WP3 enabled us to identify and optimise a range of novel durable, non-slip flooring products.
• Testing were carried out using standardised, industry approved laboratory test methods and procedures to guarantee that the developed materials met all necessary industry and legislative criteria.
• Test material of PVC floor coverings were produced in pilot scale both as plastisol and as dry blend.
• Two formulations using extrusion for mixing of master batch and base formulation and three modifications using calendaring for mixing of master batch and base formulation were prepared in the pilot plant of the IRG partner. Both processes resulted in samples with good slip performance also in the wet. The next development step will focus on improving other characteristics of the new flooring.
• Further improvements could be reached in individual co-operations of flooring manufactures and RTD after the end of the Slipsafe project.
• The results of LCA and economic analysis foresee a positive scenario for the SlipSafe flooring commercialization in the coming years, in terms of the PVC to be used as a base material and in terms of the potential sales in SlipSafe flooring made by new material. Taking into consideration the economic aspects, the SlipSafe process is competitive with other floorings. SlipSafe flooring has good capacity to operate in praxis and is a sustained solution to prevent injuries to large extent in comparison with existing resilient floorings.
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