EP3056264B1

EP3056264B1 - Tinting method and tinting machine

Info

Publication number: EP3056264B1
Application number: EP15155116.5A
Authority: EP
Inventors: Salih Zeki Kurt; Özlem Caglayan Elmaci; Tolga Ustamehmetoglu
Original assignee: Betek Boya Ve Kimya Sanayi AS
Current assignee: Betek Boya Ve Kimya Sanayi AS
Priority date: 2015-02-13
Filing date: 2015-02-13
Publication date: 2023-05-10
Anticipated expiration: 2035-02-13
Also published as: EP3056264A1

Description

Technical Field of the Invention

The present invention relates to a tinting method and tinting machine for preparation of ready-to-use paint mixtures.

Background of the Invention

'Tinting' refers to automatic preparation of a paint having a selected color (e.g. a color having a designated symbol/number, and selected from a colors list prepared by a commercial paint company). Said preparation is mainly performed by entering a designated symbol/number referring to said selected color to a tinting machine (usually operated using a computer); then the tinting machine introduces pre-determined or calculated amounts of several liquid constituents into a paint container (e.g. a paint can) automatically and the liquid constituents in the container are mixed; thus a paint mixture is obtained automatically. Commonly regarded properties of a paint mixture include pH, density (unit of which is e.g. g/mL), gloss, hiding power (unit of which is e.g. m²/L), and color. Values of said properties sholud not change dramatically between several paint mixtures of same symbol/number. That is, a paint mixture prepared for a symbol/number selected from a list shall exhibit properties around expected values. For instance, color of two paint samples having same symbol/number/product code (i.e. two samples obtained from two individual preparations of same paint product), from several paint cans which are prepared on different days or using different tinting machines, should not be perceived (e.g. by consumer) considerably different from each other. The difference between two colors is quantified as 'delta E' (dE). Color differences with dE values lower than 1 are considered as just noticeable, or barely noticeable or practically not noticeable, thus such dE values for two individual paint samples are required to be below 1.
Tinting machines and methods in state of the art provide preparation of ready-to-sell paint mixtures in containers (e.g sealable paint cans). Usually, a customer orders a can of paint with color selected from a list where different colors are listed in respective symbols/numbers/product codes, and the customer decides also the size of the container, e.g. a sealable paint container for containing up to a maximum 15 liters paint. Then, an operator enters the color selection and size to a tinting machine usually over a digital interface or a computer program interface. The tinting machine automatically loads a constant amount of a base into the can. Said constant amount is pre-programmed into the machine for each can size selection, such that total volume of a paint mixture does not exceed the capacity of the can. Furthermore, according to the color selection of the customer, one or more pigment pastes can be added into the can for obtainment of the selected color upon mixing the base and pigment paste(s). The added amount(s) of the pigment paste(s) are calculated beforehand and pre-programmed into the machine for each can size selection, such that for a certain paint color, paint mixtures prepared in having different sizes contain different respective amounts of bases, and respectively different amounts of pigment paste(s) are required for obtainment of said certain color for each can size i.e. for each base amount. It is obvious that, in order to prepare paint mixtures of different colors, different amounts of pigment paste(s) are to be mixed with a certain volume of a base.
At the end of such ready-to-sell paint preparation process using conventional tinting machines and methods, the total volumes of paint mixtures vary for different colors. Thus, remaining volume for a certain size paint can is inconsistent from color to color, which is perceived as an inconsistency by consumers.
Since the size of preparation of paints in a factory is in a higher order of magnitude in comparison with that in a tinting machine, it is possible to load each paint container with same amounts of paint whatever the color is. When a customer orders a can of paint from a factory, the (volumetric) amount of the paint differs from the amount of a second can of paint from a tinting machine, even when both said paints have the same symbol/number/product code. This is also perceived by customers as an inconsistency. These perceptions may even lead to a tarnished brand image for a corporation commercializing paints prepared by tinting.
Thus, such inconsistencies should be overcome for maintaining and improving the brand image.

Objects of the Invention

Primary object of the present invention is to overcome the abovementioned shortcomings of the prior art.
US 5460297 A discloses a paint tinting system including a plurality of colorant dispensing subsystems interconnected with a clear filler dispensing subsystem. This prior art document refers to the problem of volumetric inconsistency at tinting. Recipes maintained within a microprocessor control the dispensing of fixed volumes of colorant into dispensing tubes with such volumes being maintained between volumes of clear filler. Valve actuation introduces the colorant into a can of base paint, along with sufficient clear filler to assure a full measure of paint is generated. The subsystems provide for recirculation of the colorants and clear filler to assure that the same remain homogenous at the time dispensing is required.
US 2005/092386 A1 teaches a combination of gravimetric and volumetric fluid dispenser including a scale linked to a controller. The controller is linked to a plurality of two stage valves which control the dispensing of large quantities of base materials. The controller is also linked to a plurality of nutating pumps which together with the controller controls the dispensing of smaller quantities of additive materials. The dispensing system disclosed is particularly useful for paints or other liquid formulations where larger quantities of base materials are added by weight.
Another object of the present invention is to provide a tinting method wherein volumetric consistency by preparation of paint mixtures is achieved for a paint of any color.
Yet another object of the present invention is to provide a tinting apparatus wherein volumetric consistency by preparation of paint mixtures is achieved for a paint of any color.

Summary of the Invention

The present invention proposes a tinting machine pre-programmed for preparation of paint mixtures of various target colors in a paint container having a size selected from a set of various sizes designated for various target volumes of paint mixtures, which target volumes being pre-programmed to said tinting machine; said paint container being pre-loaded with a base having a certain volumetric amount designated in accordance with said size, and said tinting machine comprising a plurality of pigment paste reservoirs for containing pigment pastes having various colors, and for transferring said pigment pastes into paint containers; wherein the tinting machine further comprises a complementary paste reservoir for containing a complementary paste and for transferring said complementary paste into paint containers, such that, in use, the complementary paste is dispersed in a pre-programmed complementary volumetric amount and thereby same final volume of paint mixture is obtained, said final volume is equal to the target volume, and is valid for paint mixtures of all colors. The present invention further proposes a tinting method for preparation of paint mixtures having a final volume, which is valid for all colors.

Detailed Description of the Invention

The present invention proposes a tinting method as per the subject-matter of claim 4 and a tinting system comprising a tinting machine as per the subject-matter of claim 1 for preparation of ready-to-use paint mixtures.
The present invention proposes a tinting method and machine for preparation of paint mixtures in consistent volumetric amounts, regardless of the color of a ready-to-sell can of paint. Volumetric amount of a paint mixture to be filled into a paint can is pre-determined such that said amount does not exceed the capacity of the paint can; and various respective volumetric amounts are to be pre-determined for each size of paint cans for use in tinting. A tinting machine according to the present invention can be set for preparing paint mixtures to be sold in paint cans in various sizes. In accordance with customer order, a respective paint can having suitable size is selected for loading with paint mixture using the tinting method and machine according to the present invention.
A target color pre-programmed to a tinting machine is entered and a selected can size is input to the tinting machine. A can to be used with the tinting method and machine according to the present invention is pre-loaded with a base having a pre-determined volume designated for the size of the can. Said pre-determined volume of base is same for a respective size of paint can, which is to be loaded with paint mixture having a color pre-programmed into the tinting machine. Also, where applicable, a pre-programmed amount of pigment paste(s) is introduced into the paint can for provision of target color to the paint mixture. The target color may necessitate introduction of one or more pigment paste of pre-calculated volumetric ratio(s) over base, i.e. pre-programmed amounts of said pigment paste(s) are mixed with base having pre-determined base volumes, where applicable.
Consistent volume in final product, i.e. in the ready-to-sell paint mixture, is obtained by introduction of an amount of a complementary paste into the paint can. Said amount varies for each target color and each can size; and is pre-determined and pre-programmed to the tinting machine; such that paint can having a certain size input/entered into the tinting machine, contains a consistent volume of paint mixture regardless of the target color.
Provision of such volumetric consistency is especially of greater importance for paints prepared using a base providing low transparency, and moderate-to-high hiding power to the paints. That is because such high hiding power and low transparency is obtained with titanium dioxide (TiO₂) content of a base, which is a significant cost item in paint preparations; and paint preparations with high titanium dioxide content are difficult to remedy in case of ending up with an undesired color.
It is very critical to maintain the target color even with the abovementioned addition of the complementary paste, since a light colored mixture is prone to change its color after such addition. Therefore the properties of the complementary paste are to be compatible with those of the base, and those of the mixture of base and pigment paste(s). This can be achieved with a complementary paste having following preferred features:

the pH of the complementary paste ranges between 7 and 9,
properties of the filler used by preparation of the complementary paste is comparable with the properties of the filler used by preparation of the base, such that the quotient of hiding powers of base and of the complementary paste is within the range between 0.9 and 1.1.

The complementary paste comprises following ingredients in following weight percentages with respect to the total weight of the compensation paste:

filler, 50% to 70% (w/w), more preferably 55% to 65% (w/w),
additives such as viscosity, flow and foaming regulators, as well as, dispersion agents, biocides, in types and amounts used in conventional interior or exterior paint preparations, and
water, in complementary amount.

In a preferred embodiment according to the present invention, the paints with target colors which are light colors (i.e. having a L-value of 85 or higher, with regard to CIELab's lightness scale ranging the lightness between 0 and 100) prepared with admixing of pre-programmed amounts of pigment pastes ranging between 0 and 4% (v/v), more preferably between 0% and 3.5%, based on base volume, wherein the base having a high hiding power (i.e. 98% and higher, at 7 m²/L). In another preferred embodiment according to the present invention, said amount of pigment paste ranges between 3% and 6% (v/v), more preferably between 3.5% and 5% (v/v) based on base volume, wherein the base having a moderate hiding power (i.e. a hiding power thereof is at least 50% and lower than 98%, at 7 m²/L).
Notwithstanding that the problem solved with the tinting method and machine according to the present invention, implementation of the tinting method and machine invention with minimal modifications performed by a person skilled in the art which reads and understands this document, in preparation of paints having a lower hiding power and/or a darker color. Hence, it is possible to prepare ready-to-sell paints of any color, with a single tinting machine performing the method according to the present invention.

EXAM PLES

The following examples are intended only to further illustrate the invention and are not intended to limit the scope of the invention that is defined by the claims.
Performance of the method according to the present invention was tested for eight paints which are commercialized prepared also using tinting machines. For each of said eight paints having various colors selected from a color card for preprogramming to a tinting machine according to the present invention, a first sample (samples 1 to 8) was prepared according to conventional tinting method, and a respective second sample (samples 1' to 8') was prepared according to the method proposed hereby by the inventors.

The volumetric amounts of ingredients used by preparation of samples 1 to 8 prepared according to above explained conventional tinting method are shown in Table 1. Columns 1 to 4 of Table 1 respectively correspond to sample ID numbers each having a respective target color, base volumes (L), total pigment paste volumes (L) to achieve the respective target colors, and total volume of samples obtained by mixing said bases with pigment pastes. As seen in Column 4, final volumes of paint mixtures prepared according to the conventional method differ between target colors.

Table 1. Volumetric constitutions for samples 1-8 (prepared according to conventional tinting method)

Column 1	Column 2	Column 3	Column 4
Sample #	Base volume (L)	Pigment pastes volume (L)	Total volume (L)
1	12.20	0.02034	12.220
2	12.20	0.03037	12.230
3	12.20	0.02134	12.221
4	12.20	0.0117	12.212
5	12.20	0.0722	12.272
6	12.20	0.0262	12.226
7	12.20	0.0593	12.259
8	12.20	0.0153	12.215

The volumetric amounts of ingredients used by preparation of samples 1' to 8' prepared with to the method according to the present invention are shown in Table 2. Columns 1 to 5 of Table 2 respectively correspond to sample ID numbers each having a respective target color, base volumes (L), total pigment paste volumes (L) to achieve the respective target colors, complementary paste volumes (L) introduced for achieving a standard sample final volume for each sample; and total volume of samples obtained by mixing said bases with pigment pastes. As seen in Column 5, final volumes of paint mixtures prepared with the method according to the present invention is valid for each target color, thus a consistent target volume is achieved for each sample.

Table 2. Volumetric constitutions for samples 1'-8' (prepared according to the tinting method according to the present invention)

Column 1	Column 2	Column 3	Column 4	Column 5
Sample #	Base volume (L)	Pigment pastes volume (L)	Complementary paste volume (L)	Total volume (L)
1'	14.85	0.02475	0.12524	15
2'	14.85	0.03696	0.11303	15
3'	14.85	0.02598	0.12402	15
4'	14.85	0.01424	0.13576	15
5'	14.85	0.08789	0.06212	15
6'	14.85	0.03189	0.11811	15
7'	14.85	0.07218	0.07782	15
8'	14.85	0.01863	0.13138	15

The complementary pastes used in samples 1' to 8' have the same composition, thus in each of said samples a single complementary paste formulation was employed. Each sample ID number (1-8 or 1'-8') corresponds to another target color, and it was tested if samples prepared according to the present invention (samples 1' to 8') show properties comparable with samples prepared using conventional method (samples 1 to 8). Said properties are listed as: dE (color difference measured according to the version of DIN6174 valid in 1 February 2015), hiding power (measured according to the latest Turkish standard method TS EN ISO 6504-3 valid in 1 February 2015), gloss (measured using Micro TRI Glossmeter by BYK Gardner, according to the latest Turkish standard method TS 4318 EN ISO 2813 valid in 1 February 2015), and whiteness (measured according to the latest Turkish standard method TS 7169 valid in 1 February 2015). Color differences (dE values) obtained for each corresponding sample pair (e.g. samples 1 and 1') are given in Table 3. The dE values being in the lower part of the interval 0 and 1 (i.e. close to zero), show that each sample prepared with the method according to the present invention have an indistinguishably (i.e. indistinguishably similar for ordinary human eyes) small color difference from respective target colors. Table 3. dE values for sample pairs for each target color.

Compared samples dE

1 and 1' 0.15

2 and 2' 0.26

3 and 3' 0.07

4 and 4' 0.12

5 and 5' 0.2

6 and 6' 0.26

7 and 7' 0.2

8 and 8' 0.16

Tables 4 and 5 comparatively show average values of several properties of samples prepared using conventional method, and average values of those properties after adding and mixing of complementary paste in a volumetric ratio of 1% based on the volumes of said samples prepared using conventional method. The samples 1 to 4 are interior paints, and samples 5 to 8 are exterior paints. Tables (Table 4 and 5) are prepared separately, since bases employed in preparation of interior and exterior paints are different. Admixing of complementary paste into samples 1-8 in a volumetric ratio of 1% with respect to based on the volumes of said samples prepared using conventional method did maintain the property values acceptable.

Table 4. Effects of admixing complementary paste on sample properties (for samples 1 to 4).

Property	Samples 1-4	Upon admixing with complementary paste
pH	7.98	7.92
Density (g/mL)	1.33	1.33
Gloss	5.2 / 44	4.8 / 38.9
Hiding power (%, at 7 m²/L)	98.60	98.70
Whiteness	87.80	87.20

Table 5. Effects of admixing complementary paste on sample properties (for samples 5 to 8).

Property	Samples 5-8	Upon admixing with complementary paste
pH	7.80	7.83
Density (g/mL)	1.58	1.58
Gloss	1.8 / 1.0	1.8 / 0.9
Hiding power (%, at 7 m²/L)	97.60	97.40
Whiteness	73.30	73.20

Thus, the present invention proposes a tinting machine pre-programmed for preparation of paint mixtures of various target colors in a paint container having a size selected from a set of various sizes designated for various target volumes of paint mixtures, which target volumes being pre-programmed to said tinting machine; said paint container being pre-loaded with a base having a certain volumetric amount designated in accordance with said size, and said tinting machine comprising a plurality of pigment paste reservoirs for containing pigment pastes having various colors, and for transferring said pigment pastes into paint containers; wherein the tinting machine further comprises a complementary paste reservoir for containing a complementary paste and for transferring said complementary paste into paint containers, such that, in use, the complementary paste is dispersed in a pre-programmed complementary volumetric amount and thereby same final volume of paint mixture is obtained, said final volume is equal to the target volume, and is valid for paint mixtures of all colors.
According to the present invention, the complementary paste has a pH value ranging between 7 and 9; and the quotient of hiding powers of base and of the complementary paste is within the range between 0.9 and 1.1.
The complementary paste is aqueous, and comprises 50 to 70 weight percent of filler with respect to the total weight of the compensation paste.
The base is optionally for interior paints, or for exterior paints.
Alternatively, the base is a first base having a hiding power of at least 98%, or a second base having a hiding power of at least 50% and lower than 98%.
The present invention further proposes a tinting method according to claim 4 for preparation of a ready-to-sell liquid paint mixture in a paint container, said paint mixture having a target color pre-programmed into a tinting machine programmed for preparation of various paint mixtures having different target colors and one or more target volumes.
One or more pigment paste is automatically introduced into the paint container prior to or during the step c), and the amount of introduced complementary paste is pre-programmed such that the final volume of the ingredients inside the paint container is equal to target volume, by being the sum of volumetric amounts of pigment paste and base is equal to the difference between the target volume and the volumetric amount of the base.
The complementary paste has a pH value ranging between 7 and 9; and the quotient of hiding powers of base and of the complementary paste is within the range between 0.9 and 1.1.
The complementary paste is aqueous and comprises 50 to 70 weight percent of filler with respect to the total weight of the compensation paste. Preferably a first base is used for preparation of interior paints, and a second base is used for preparation of exterior paints.
Alternatively, the base used in the method according to the present invention is selected from a first base having a hiding power of at least 98%, and a second base having a hiding power of at least 50% and lower than 98%. When said first base is used, the volumetric amount of pigment pastes preferably range between 0 and 4%, more preferably between 0 and 3.5% based on volume of the first base; and when said second base is used, the volumetric amount of pigment pastes range between 3% and 6%, more preferably between 3.5% and 5% based on volume of the second base.
The complementary paste is an aqueous mixture comprising 50 to 70 weight percent of filler with respect to the total weight of said compensation paste. With the tinting method and system according to the invention, it is possible to fill a ready-to-sell paint container e.g. paint can with a pre-determined total amount of paint, without affecting the properties of the paint. Thus the following objects are achieved by the present invention:

the abovementioned shortcomings of the prior art are overcome,
a tinting method wherein volumetric consistency by preparation of paint mixtures is achieved at paint for any color, is provided.
a tinting apparatus wherein volumetric consistency by preparation of paint mixtures is achieved at paint for any color, is provided.

Claims

A tinting system comprising a tinting machine which is pre-programmed for preparation of paint mixtures of various target colors in paint containers having a size selected from a set of various sizes designated for various target volumes of paint mixtures, which target volumes being pre-programmed to said tinting machine;
the system further comprises such paint container which is pre-loaded with a base having a certain volumetric amount designated in accordance with said size, and

the system further comprises in said tinting machine, a plurality of pigment paste reservoirs containing pigment pastes having various colors, and arranged for transferring said pigment pastes into paint containers

the tinting system further comprises in the tinting machine, a complementary paste reservoir containing an aqueous complementary paste, and arranged for transferring said complementary paste into paint containers, wherein the system is arranged to, in use,

disperse the complementary paste in a pre-programmed complementary volumetric amount and thereby obtaining same final volume of paint mixture, said final volume being equal to the target volume, and being valid for paint mixtures of all colors; and

characterized in that the complementary paste comprises 50 to 70 weight percent of filler with respect to its total weight, the complementary paste has a pH value ranging between 7 and 9; and the quotient of hiding powers of base and of the complementary paste is within the range between 0.9 and 1.1.
The system according to any of the Claim 1, wherein the base is for interior paints, or for exterior paints.
The system according to any of the Claims 1 to 2, wherein the base is a first base having a hiding power of at least 98%, or a second base having a hiding power of at least 50% and lower than 98%.
A tinting method for preparation of a ready-to-sell liquid paint mixture in a paint container, said paint mixture having a target color pre-programmed into a tinting machine in a tinting system, the tinting machine being programmed for preparation of various paint mixtures having different target colors and one or more target volumes by implementing the method comprising the steps of:
a) placing a paint container for material transfer from the tinting machine into the paint container; said paint container having a size selected from a set of various sizes designated for various target volumes of paint mixtures, and said paint container being pre-loaded with a base having a certain volumetric amount designated in accordance with said size,

b) setting of a target color and a target volume for the paint mixture to be prepared, into the tinting machine,

c) automatic introduction by the tinting machine, of an aqueous complementary paste into the paint container, said complementary paste having a pre-programmed amount designated for the target color, such that the final volume of the paint mixture is equal to target volume which is valid for paint mixtures of all colors,

d) mixing ingredients inside the paint container,

wherein the complementary paste is dispersed in a pre-programmed complementary volumetric amount to obtain same final volume of paint mixture, said final volume being equal to the target volume, and being valid for paint mixtures of all colors, and

characterized in that the complementary paste comprises 50 to 70 weight percent of filler with respect 30 to its total weight, and has a pH value ranging between 7 and 9; and the quotient of hiding powers of base and of the complementary paste is within the range between 0.9 and 1.1.
A tinting method according to the Claim 4, wherein one or more pigment paste is automatically introduced into the paint container prior to or during the step c), and the amount of introduced complementary paste is pre-programmed such that the final volume of the ingredients inside the paint container is equal to target volume, by being the sum of volumetric amounts of pigment paste and base is equal to the difference between the target volume and the volumetric amount of the base.
A tinting method according to any of the Claims 4 or 5, wherein a first base is used for preparation of interior paints, and a second base is used for preparation of exterior paints.
A tinting method according to any of the Claims 4 to 6, wherein the base is selected from a first base having a hiding power of at least 98%, and a second base having a hiding power of at least 50% and lower than 98%.
A tinting method according to the Claim 6, wherein the volumetric amount of pigment pastes range between 0 and 4%, more preferably between 0 and 3.5% based on volume of the first base.
A tinting method according to the Claim 6, wherein the volumetric amount of pigment pastes range between 3% and 6%, more preferably between 3.5% and 5% based on volume of the second base.