Patent Application
20070031640
The present invention relates to a floor covering having an exposed surface with substantially the same gloss level and at least two portions having different tactile surface characteristics, and the method of making it. The floor covering is made by forming a high performance coating including texture particles on a substrate, at least partially curing the high performance coating, and then while controlling the temperature of the high performance coating below the melting point temperature or softening point temperature of the texture particles and above the temperature at which the texture particles deform under the applied mechanical embossing pressure, subjecting the first and second portions to different mechanical embossing conditions. Preferably, the temperature of the high performance coating during the mechanical embossing is between approximately 10° F. and 400° F. below the melting point temperature or softening point temperature of low melting point texture particles and between approximately 250° F. and 450° F. below the melting point temperature or softening point temperature of high melting point texture particles
Texture is a tactile surface characteristic which is synonymous with roughness. It can be felt by moving a finger over a surface with light pressure and can be quantified by average peak density (RPc). Average RPc is the average of a number, such as 30, PRc values as can be measured by a surface texture meter of profilometer, such as a Surfak-SV/Pro/SJ surface texture meter or profilometer sold by Mitutoyo. The higher the average peak density, the rougher the surface texture.
As used herein, “substantially the same gloss level” means a difference in 60° gloss level of 5.0 or less. The 60° gloss level of known prior art floor products having different areas of roughness vary by at least 5.5. With regard to the present examples, gloss level was measured with a BYK gloss meter.
As used herein, a “high performance coating” means (a) a water-based thermal curable coating comprising a resin such as waterborne epoxy, polyurethane aqueous dispersion, or polyvinyl chloride aqueous dispersion, a crosslinker such as urea formaldehyde or melamine formaldehyde, one or more catalysts and one or more surfactants, (b) a water-based radiation curable coating comprising a resin such as acrylic emulsion, polyurethane aqueous dispersion, acrylated polyether, acrylated polyester or acrylated urethane, one or more surfactants and at least one photoinitiator, (c) a 100% solids thermal curable coating comprising a resin such as polyester polyol, polyether polyol or urethane, a crosslinker such as urea formaldehyde or melamine formaldehyde, at least one thermal catalyst, one or more surfactants, (d) a 100% solids thermal curable coating comprising a resin such as acrylated polyether, acrylated polyester or acrylated urethane, at least one thermal initiator and at least one surfactant, (e) 100% solids radiation curable coating comprising a resin such as acrylated polyether, acrylated polyester or acrylate urethane, at least one surfactant and at least one photoinitiator, (f) a 100% solids thermal/radiation dual cure coating comprising at least one of the resins listed in (e) above, at least one of the resins listed in (c) and (d) above, a crosslinker such as urea formaldehyde or melamine formaldehyde, at least one photoinitiator, at least one thermal catalyst and one or more surfactants, or (g) a water-based thermal/radiation dual cure coating comprising at least one of the resins listed in (a) above, at least one of the resins listed in (b) above, a crosslinker such as urea formaldehyde or melamine formaldehyde, at least one photoinitiator, one or more catalysts and one or more surfactants. Each of the above-identified high performance coatings can include additives known in the art, including flatting agents, pigments, coalescing solvents and defoamers.
The floor covering of the present invention has an exposed surface with substantially the same gloss level and at least two portions having different tactile surface characteristics, and the method of making it. The difference in the tactile surface characteristics between the two portions is at least an average RPc of 4. The floor covering includes a substrate and a high performance coating overlying the substrate. The high performance coating comprises texture particles, which may be organic polymer particles, such as nylon particles, man-made wax particles, natural wax particles, polyolefin particles, Teflon particles, polyetheretherketone (PEEK) particles, ethylene and chlorotrifluoroethylene copolymer particles, polyester particles, urea-formaldehyde polymer particles, polyacrylate particles, polycarbonate particles, polyvinylchloride particles, polyimide particles, or combinations thereof.
Teflon particles and PEEK particles have high melting points, greater than 575° F. The other listed examples of texture particles have low melting points no greater than 575° F. The operating temperature used to produce the floor coverings depends on the materials forming the floor substrate, as well as the melting point or softening point of the texture particles. Therefore, the temperature of the high performance coating is controlled below the melting point temperature or softening point temperature of the texture particles and above the temperature at which the texture particles deform under the applied mechanical embossing pressure, preferably between approximately 10° F. and 400° F. below the melting point temperature or softening point temperature of low melting point or softening point texture particles and between approximately 250° F. and 450° F. below the melting point temperature or softening point temperature of high melting point or softening point texture particles. These temperatures permit deforming of the texture particles under the desired mechanical embossing conditions while not damaging the floor covering substrate.
The flooring coverings with variable texture may have any desired gloss level, for example a 60° gloss level from about 2 to about 60 or above 60. The invention specifically includes ultra low gloss floor coverings having a 60° gloss level from about 2 to about 16, and more preferably from about 6 to about 11.
The floor covering has substantially the same gloss level, i.e. the difference in 60° gloss level across the floor covering is no greater than 5.0 as measured with a BYK gloss meter. Preferably the difference in 60° gloss level across the floor covering of the present invention is less than 3 and more preferably less than 1.
The floor covering is made by forming a high performance coating including the texture particles on a substrate, at least partially curing the high performance coating, and then while controlling the temperature of the high performance coating below the melting point temperature or softening point temperature of the texture particles and above the temperature at which the texture particles deform under the applied mechanical embossing pressure, preferably between approximately 10° F. and 400° F. below the melting point temperature or softening point temperature of low melting point or softening point texture particles and between approximately 250° F. and 450° F. below the melting point temperature or softening point temperature of high melting point or softening point texture particles, subjecting the first and second portions to different mechanical embossing conditions. The different conditions include different average pressures, different embossing temperatures, and different average pressures and embossing temperatures. The difference in average pressures can be obtained by overall mechanical embossing of a chemically embossed substrate or using different mechanical embossing profiles, for example.
FIGS. 4 to 22 are graphs showing the surface profiles of the various samples as measured by the Mitutoyo Surface meter.
FIGS. 23 to 35 are process flow charts showing examples of various methods and substrates of the present invention.
The floor covering of the present invention has an exposed surface with two portions having different tactile surface characteristics, but substantially the same gloss level. The difference in the tactile surface characteristics between the first and second portions is at least an average RPc of 4.
In one embodiment, the floor covering has a 60° gloss level across the floor covering of no greater than about 5. This yields a floor covering having a similar look due to the gloss, but with a different feel. To improve this effect, it is preferred that the 600 gloss level across the floor covering be no greater than about 3 or more preferably no greater than about 1.
To be able to feel the difference in the tactile surface characteristic between the first portion and the second portion, the difference in average RPc must be at least 4. To more easily feel the difference, the difference in average RPc should be at least 10. To be appealing to the consumer, the difference in the tactile surface characteristics between the first and second portions should have an average RPc of less than 75.
Typically, the floor covering comprises at least a substrate and a high performance coating overlying the substrate. The substrate may include a PVC clear coat, a polyolefin clear coat, a vinyl composition layer, a print layer, a foamable layer, a hot melt composition layer, a felt, a glass mat, laminate, wood or combinations thereof. The substrate is not critical to the invention and includes any known flooring substrate including a PVC clear coat, a polyolefin clear coat, a vinyl composition layer, a print layer, a foamable layer, a hot melt composition layer, a felt, a glass mat or combinations thereof. For the purposes of this invention, the substrate is all the layers below the high performance coating.
The high performance coating includes texture particles which are large enough to produce a textured surface when the high performance coating is applied to a substrate. The texture particles comprise an organic polymer, including nylon, man-made wax, natural wax, polyolefin, Teflon, PEEK (Polyetheretherketone), ECTFE (ethylene and chlorotrifluoroethylene copolymer), polyester particles, urea-formaldehyde polymer particles, polyacrylate particles, polycarbonate particles, polyvinylchloride particles, polyimide particles, or any other material which will soften at the mechanical embossing conditions (temperature and pressure) of the process.
It is critical for the temperature of the exposed surface of the high performance coating to be below the melting point temperature or softening point temperature of the texture particles and above the temperature at which the texture particles deform under the applied mechanical embossing pressure. This is typically between approximately 10° F. and 400° F. below the melting point temperature or softening point temperature of low melting point or softening point texture particles and between approximately 250° F. and 450° F. below the melting point temperature or softening point temperature of high melting point or softening point texture particles, as the high performance coating is mechanically embossed. This permits the texture particles to be reshaped creating the difference in the tactile surface characteristics.
Another critical parameter is the average pressure applied by the mechanical embossing tool on the texture particles of the high performance coating. The protrusions on the mechanical embossing tool are referred to as peaks and the down areas are referred to as valleys. The peaks typically have flat upper surfaces and resemble plateaus. When the embossing tool presses on the floor substrate, there will be different pressures created by the tool on the substrate surface due to the peak areas and valley areas on the tool. The peak areas on the tool will create high pressure on the substrate. This will smooth out the texture/roughness created by the texture particles in the high performance top coating.
Clearly, the valley areas on the mechanical embossing tool will create less pressure on the texture particles in the high performance top coating. This difference in average pressure is one method to get variable texture from the same textured top coating formula. See
Typically, the mechanical embossing tool is an overall mechanical embossing tool, which applies the same pattern over the entire width of the high performance coated floor covering substrate. The temperature of the mechanical embossing tool is kept below 110° F. or a temperature necessary to set the mechanical embossing.
The difference in the first average pressure and second average pressure can result from the peaks on the mechanical embossing tool corresponding to the first area having greater height than the peaks corresponding to the second area. In another embodiment, the difference in the first average pressure and second average pressure can result from the peaks on the mechanical embossing tool having the same height, but the peaks corresponding to the first area having widths that are greater than the widths of the peaks corresponding to the second area.
Any method that could cause pressure differences during the mechanical embossing of the texture coating surface will create the variable textures on the finished floor products. For example, as shown in
The other parameters that affect the variable texture include substrate temperature and the melting point or softening point of the texture particles in the coating. The temperature difference between the melting point temperature or softening point temperature of the texture particles and the temperature of the high performance coating during the mechanical embossing process should be between approximately 10° F. and 400° F. for low melting point or softening point texture particles and between approximately 250° F. and 450° F. below the melting point temperature or softening point temperature for high melting point or softening point texture particles to ensure that the particles can be reshaped without melting or softening.
When the process conditions are kept the same, including temperature of the substrate surface, the melting point or softening point of the texture particles, the coating formulation, and the same chemically embossed substrate, different variable textures can be created by using different mechanical embossing tools. See
The data set forth in the charts labeled “Data-072805” set forth the operating parameters and 60° gloss level of a number of examples made by the process of the present invention. The dates and pattern numbers correspond to the dates and pattern numbers set forth in the column “Level” in the chart labeled “One-way ANOVA: RPc versus Sample ID. Level “041205 X-5” corresponds to pattern X5 and date Apr. 12, 2005 in the Data-072805 chart. The letter “G” in the pattern number means the RPc measurements were taken in the grout lines of the pattern. Without the letter “G” in the pattern number, the RPc measurements were made in the field or up areas of the pattern. The average depth, in mils, of the mechanical embossing rolls used to form the textures listed in the line labeled “Emboss Texture” are as follows:
The temperatures set forth in the Data-072805 are ° F. The “Into Embosser (face/back)” with the “-” symbol are estimations.
The One-way ANOVA chart sets forth the mean and standard deviation for 30 measurements of RPc per sample. See the definitions following the charts.
Each asterisk represents a sample mean. Each set of parentheses encloses a 95% confidence interval for the mean of a population. You can be 95% confident that the population mean for each level is within the corresponding interval. If the intervals for two means do not overlap, it suggests that the population means are different. In other words, there is a significant statistical difference between two RPc values if the interval for the two means do not overlap. However, above individual 95% confidence intervals for mean is based on pooled standard deviation (StDev)—an estimate of the common standard deviation for all samples. It is necessary to redo the statistic analysis for specific group of samples needed to be compared with. For example, the One-way ANOVA chart below shows the analysis results to compare sample “041205 X-5” and sample “061405 X-5”. The analysis results indicated that there is a significant statistical difference on measured RPc values between the two floor samples made on Apr. 12, 2005 and Jun. 14, 2005, even though they have the same pattern number X-5. The data set forth in the chart labeled “Data-072805” can explain how to make such variable textures on the same pattern.
Source: Each potential cause of variability in the data is called a source. In a one-way ANOVA, two sources of variability are analyzed: the factor of interest and error.
Degrees of freedom (DF): The degrees of freedom are used to calculate the mean square (MS). In general, the degrees of freedom measure how much “independent” information is available to calculate each sum of squares (SS).
Note
DF total=DF for the factor+DF for error
DF total=n−1, where n is the total number of observations
DF for factor=k−1, where k is the number of levels of the factor
DF for error=n−k
Sum of squares (SS): The sum of squares is also called the sum of the squared deviations. The total sum of squares measures the total variability in the data. This variability is made up of two sources:
Mean squares (MS): The mean square for each source is simply the sum of squares (SS) divided by the degrees of freedom (DF). The mean squares for error are an estimate of the variance in the data left over after differences in the means have been accounted for.
F: F is the statistic used to test the hypothesis that all the factor level means are equal. It is calculated as the mean square for the factor divided by the mean squares for error. F is used to determine the p-value.
p-value (P): P is the probability that you would have obtained samples as different (or more different) if there really is no difference between the level means in the population. Use the p-value to decide if the means are different:
S: see Pooled StDev below.
R-squared (R-Sq): The coefficient of determination or multiple determinations (in multiple regressions). R-Sq is the percentage of total variation in the response that is explained by predictors or factors in the model. In general, the higher the R-Sq, the better the model fits your data. R-Sq is always between 0 and N: The number of observations included for each level of the factor.
R-squared adjusted (R-Sq (adj): Accounts for the number of predictors or factors in your model. Adjusted R2 is useful for comparing models with different numbers of predictors or factors. For example, adjusted may actually decrease when another predictor is added to the model, because any decrease in error sum of squares may be offset by the loss of the degree of freedom.
Level: A one-way ANOVA compares the means for several groups. The groups are called the levels of the factor in the analysis.
N: The number of observations for the level.
Mean: The mean of the observations for the indicated factor level.
Standard deviation (StDev): The StDev for a given level is the sample standard deviation calculated using the observations for that level.
Pooled standard deviation (Pooled StDev): An estimate of the standard deviation for the population. Analysis of variance procedures assume that all levels have the same population standard deviation. This standard deviation is estimated by “pooling” information about the standard deviations for all the levels to get the pooled standard deviation.
The definition of RPc is set forth in the Mitutoyo Surface Texture Parameter User's Manual. The set-up conditions used for the profilometer readings and graphs of surface profiles are set forth in the chart labeled “Set-up conditions used for profilometer readings” below.
Set-Up Conditions Used for Profilometer Readings
The graphs of micro inches vs. inches (FIGS. 4 to 22) show the surface profiles of the various samples as measured by the Mitutoyo Surface meter. The charts were selected of the samples having a RPC close to the mean RPC of the 30 measurements. The number following the date and pattern number is the measurement. “041205 X-5 21 (RPc=22.64)” was the 21st RPc measurement of pattern X5 made on Apr. 12, 2005. The measured average RPc value was 22.64.
The
Various methods and substrates of the present invention are shown in the Process Flow Charts Method 1 to Method 12 (FIGS. 23 to 35). The methods are not limited to substantially the same gloss level between the different textured areas. The substrates can also include wood and laminates. Further, the substrate could be a film, which after being mechanically embossed is laminated or adhered to another substrate, or the film can be simultaneously mechanically embossed and laminated to another substrate.
The partial curing of the high performance coating can be accomplished by heating the coating or subjecting the coating to radiation curing for a limited amount of time. The radiation curing can be UV curing or e-beam curing. The thickness of the high performance coating is preferably about 5μ to about 75μ, more preferably about 12μ to about 50μ. After the high performance coating is mechanically embossed, it can be cured further, for example, by subjecting it to additional radiation.
| Number | Date | Country | |
|---|---|---|---|
| 60704536 | Aug 2005 | US |
