Rheological method for rapidly detecting long-term storage stability of color paste

Abstract

The invention relates to a rheological method for rapidly detecting the long-term storage stability of color paste. The rheological method comprises the steps of pretreatment of color paste to be detected, rheological testing and data processing and analysis. The rheological method for rapidly detecting the long-term storage stability of the color paste is in-situ detection, physical parameters related to the long-term storage stability of the color paste can be efficiently obtained and effectively quantified through rheological detection based on an oscillation mode, and the long-term storage stability of the color paste is predicted through calculation. According to the method, the viscoelastic physical quantity of the color paste system can be obtained in a non-destructive manner, the method can be widely applied to water-based color paste detection based on inorganic and organic pigments, and a test result can be rapidly and accurately obtained.

Description

Technical Field

[0001] The invention relates to the field of water-based pigment paste, and in particular to a rheological method for quickly detecting the long-term storage stability of a paste. Background Art

[0002] In the prior art, the long-term storage stability of water-based color pastes is difficult to quantify through experimental parameters. In long-term research and development and production practices, different water-based color pastes have different methods for judging long-term storage stability, and it is difficult to effectively predict and evaluate long-term storage stability, which makes it difficult to effectively establish a structure-activity relationship in the formulation selection to improve the storage stability of the color paste.

[0003] There are currently two methods commonly used to determine the long-term storage stability of water-based color pastes: one is to measure the viscosity change of the color paste before and after heat storage, and the other is to measure the particle size change of the color paste before and after heat storage. However, experience shows that both methods cannot accurately determine the long-term storage stability of the color paste, and the operability of establishing a correlation with the structure-activity relationship is poor.

[0004] In view of this, there is an urgent need in the art to develop a rheological method that can quickly and conveniently detect the long-term storage stability of color pastes to solve the problems existing in the prior art. Summary of the invention

[0005] Based on the above facts, the purpose of the present invention is to provide a rheological method for quickly detecting the long-term storage stability of color pastes. This method is an in-situ detection. Through rheological detection based on an oscillation mode, physical parameters related to the long-term storage stability of the color paste can be efficiently obtained and effectively quantified, and the long-term storage stability of the color paste can be predicted by calculation. Compared with methods such as measuring particle size with a particle size analyzer, the present invention can non-destructively obtain the viscoelastic physical quantity of the color paste system, and can be widely used in the detection of water-based color pastes based on inorganic and organic pigments, and can achieve rapid and accurate acquisition of test results.

[0006] The first aspect of the present invention provides a rheological method for quickly detecting the long-term storage stability of a color paste, comprising the following steps:

[0007] S1: using an oscillator to pre-treat the color paste to be tested, the pre-treating including but not limited to oscillating and dispersing the color paste to be tested;

[0008] S2: Performing a rheological test using a rheometer; the rheological test includes but is not limited to measuring the storage modulus G' of the color paste to be tested using the rheometer in an oscillation mode;

[0009] S3: Data processing and analysis.

[0010] In some embodiments of the present invention, the rheological method for rapidly detecting the long-term storage stability of the color paste specifically comprises the following steps:

[0011] S1: Use an oscillator to oscillate and disperse the color paste to be tested, and then let it stand for 30min-120min;

[0012] S2: Perform linear viscoelastic region (LVR) measurement, adjust the rheometer to the oscillation mode, and perform amplitude scanning test on the color paste to be tested after standing, wherein the frequency range is set to 0.01-1.0 Hz, the strain range is set to 0-100%, and the storage modulus G' corresponding to different strains γ is obtained by test;

[0013] S3: Plot with G' as the ordinate and γ as the abscissa, and take the maximum γ corresponding to the linear region of G' max value, the value of G' is recorded as G' lin , defining the binding energy The larger the CE value, the better the long-term storage stability of the measured color paste.

[0014] In some preferred embodiments of the present invention, in the step S1, before using an oscillator to oscillate and disperse the color paste to be tested, optionally, the step of storing the color paste to be tested at high temperature is also included; high temperature storage can accelerate the destruction of the stability of the color paste, can improve the differentiation of the calculation results, and more significantly indicate the long-term storage stability of the color paste to be tested. This step is usually suitable for measuring different color pastes to be tested, and the CE values ​​directly measured are small, which cannot reflect the difference in long-term storage stability between the color pastes to be tested. Preferably, the high temperature is 40-60°C, more preferably 50°C, and the storage time is preferably 3-15 days, more preferably 5-10 days.

[0015] In some preferred embodiments of the present invention, the oscillator in step S1 is an oscillator of model SK550, and the oscillation dispersion time is 5-20 minutes.

[0016] In some preferred embodiments of the present invention, the rheometer in step S2 is a rheometer of model Anton paar MCR301, and the test fixture in step S2 is CP-60.

[0017] In some preferred embodiments of the present invention, the frequency setting interval in step S2 is 0.05-1.0 Hz, and more preferably, the frequency is 0.1 Hz.

[0018] In other embodiments of the present invention, the rheological method for rapidly detecting the long-term storage stability of the color paste specifically comprises the following steps:

[0019] T1:

[0020] (1) Divide the color paste to be tested into two groups: RT and HS; wherein RT is a room temperature storage group, the storage temperature is 20-30°C, preferably 25°C; HS is a high temperature storage group, the storage temperature is 40-60°C, preferably 50°C; the storage time of the RT and HS groups is preferably 3-15 days, more preferably 7 days;

[0021] (2) Using an oscillator, the two groups of RT and HS color pastes to be tested are shaken and dispersed respectively after storage, and then allowed to stand for 30 minutes to 120 minutes;

[0022] (3) The rheometer was set to the rotation mode, and the RT and HS groups of color pastes were treated after standing, respectively. The constant shear rate was set in the range of 10-3000s. -1 , the processing time is 8-12s, preferably 10s;

[0023] T2: The rheometer is set to the oscillation mode, and the color pastes to be tested after the RT and HS treatments are tested respectively. The strain range is set to 0.1%-10%, the constant oscillation frequency is set to 0.01-1.0Hz, and the test time is 250-350s, preferably 300s, to obtain the corresponding storage modulus G';

[0024] T3: Plot G' as the ordinate and time t as the abscissa, and define the rate of change α = Σ|(G HS '-G RT ') / G RT '|, the smaller the change rate α, the better the long-term storage stability of the measured color paste, where G HS ' is the storage modulus of the color paste stored at high temperature, G RT ' is the storage modulus of the color paste stored at room temperature.

[0025] In some preferred embodiments of the present invention, the oscillator in step T1 is an oscillator of model SK550, and the oscillation dispersion time is 5-20 minutes.

[0026] In some preferred embodiments of the present invention, the setting interval of the constant shear rate in step T1 is 50-150s -1 More preferably, the constant shear rate is 100s -1 .

[0027] In some preferred embodiments of the present invention, the rheometer in step T2 is a rheometer of model Anton paar MCR301, and the test fixture in step S2 is CP-60.

[0028] In some preferred embodiments of the present invention, the strain interval in step T2 is preferably 0.5-10%, more preferably, the strain is 1.0%; the constant oscillation frequency is preferably 0.05-1.0 Hz, more preferably, the constant oscillation frequency is 0.1 Hz.

[0029] Beneficial effects of the present invention

[0030] In view of the deficiencies in the prior art, the present invention provides a rheological method for quickly detecting the long-term storage stability of color paste. The method is an in-situ detection method. Through rheological detection based on an oscillation mode, the physical parameters related to the long-term storage stability of the color paste can be efficiently acquired and effectively quantified, and the long-term storage stability of the color paste can be predicted by calculation. Compared with methods such as measuring the particle size with a particle size analyzer, the present invention can non-destructively obtain the viscoelastic physical quantities of the color paste system, and can be widely used in the detection of water-based color pastes based on inorganic and organic pigments, and can achieve rapid and accurate acquisition of test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a relationship diagram between G' and strain γ of inorganic bismuth vanadate color paste samples 1#-4# in Example 1.

[0032] Figure 2 This is a graph showing the relationship between G' and time t for organic phthalocyanine green slurry sample 1# in Example 2.

[0033] Figure 3 1 is a graph showing the relationship between G' and time t for organic phthalocyanine green slurry sample 2# in Example 2.

[0034] Figure 4 This is a graph showing the relationship between G' and time t for organic phthalocyanine green slurry sample 3# in Example 2.

[0035] Figure 5 This is a graph showing the relationship between G' and time t for organic phthalocyanine green slurry sample 4# in Example 2. DETAILED DESCRIPTION

[0036] In order to explain the present invention more clearly, the present invention is further described below in conjunction with specific embodiments. It should be understood by those skilled in the art that the content described below is illustrative rather than restrictive, and should not be used to limit the scope of protection of the present invention.

[0037] Example 1: Long-term storage stability test of inorganic bismuth vanadate color paste

[0038] The inorganic bismuth vanadate color pastes formed by different formulations and grinding conditions have significantly different stability after long-term storage. In this embodiment, inorganic bismuth vanadate color paste samples 1#-4# were prepared according to the formulation described in Table 1 for long-term storage stability testing, and the steps included:

[0039] S1: The inorganic bismuth vanadate color paste samples 1#-4# were respectively dispersed by oscillation using a SK550 oscillator, the oscillation program was set to gear II, the oscillation time was 10 min, and the samples were allowed to stand for 60 min after oscillation;

[0040] S2: Perform linear viscoelastic region (LVR) measurement, adjust the rheometer to oscillation mode, perform amplitude sweep test on inorganic bismuth vanadate color paste samples 1#-4# after standing in step S1, set the frequency to 0.1 Hz, set the strain range to 0-100%, and use CP-60 as the test fixture to obtain the storage modulus G' corresponding to different strains γ;

[0041] S3: With G' as the ordinate and γ as the abscissa, the relationship between G' and strain γ of samples 1#-4# is obtained after measurement, as shown in Figure 1 As shown; take G′ lin The maximum γ corresponding to the linear region (deviation value 5%) max Value, calculate the binding energy

[0042] Table 1 Formula of Inorganic Bismuth Vanadate Color Paste Samples 1#-4#

[0043]

[0044]

[0045] The results of the long-term storage stability test of inorganic bismuth vanadate color paste samples 1#-4# are shown in Table 2 below. The larger the value of the binding energy CE, the better the long-term storage stability.

[0046] Table 2 Long-term storage stability test results of inorganic bismuth vanadate color paste samples 1#-4#

[0047] Sample No. <![CDATA[G′ lin ]]> <![CDATA[γ max ]]> CE Sample 1# 0.12 8.14 7.95 Sample 2# 0.04 18.00 12.96 Sample 3# 1.62 2.55 10.53 Sample 4# 0.802 4.55 16.60

[0048] According to the results in Table 2, it can be predicted that the long-term storage stability of the inorganic bismuth vanadate color paste samples is in the following order: sample 4# > sample 2# > sample 3# > sample 1#.

[0049] Comparative Example 1: Prediction of long-term storage stability of inorganic bismuth vanadate color paste by measuring particle size

[0050] The particle size of inorganic bismuth vanadate color paste samples 1#-4# was tested to predict the long-term storage stability by measuring the initial particle size of the color paste. The test results are shown in Table 3.

[0051] Table 3 Particle size of inorganic bismuth vanadate color paste samples 1#-4#

[0052]

[0053] According to the results in Table 3, if it is believed that the smaller the particle size, the better the long-term storage stability, it can be predicted that the order of the long-term storage stability of the inorganic bismuth vanadate color paste samples is: sample 2#>sample 4#>sample 1#>sample 3#.

[0054] Comparative Example 2: Predicting the long-term storage stability of inorganic bismuth vanadate color paste by measuring viscosity

[0055] The particle size of inorganic bismuth vanadate color paste samples 1#-4# was tested, and the long-term storage stability was predicted by measuring the initial viscosity of the color paste. The test results are shown in Table 4.

[0056] Table 4 Viscosity of Inorganic Bismuth Vanadate Color Paste Samples 1#-4#

[0057]

[0058] According to the results in Table 4, if it is believed that the higher the initial viscosity, the better the long-term storage stability, it can be predicted that the order of the long-term storage stability of the inorganic bismuth vanadate color paste samples is: sample 3#>sample 4#>sample 1#>sample 2#.

[0059] The order of predicting long-term storage stability by the three methods in Example 1 and Comparative Examples 1-2 is summarized as shown in Table 5 below:

[0060] Table 5 Summary of the order of predicting long-term storage stability using the three methods in Example 1 and Comparative Examples 1-2

[0061] method Predicting long-term storage stability order Measuring initial particle size Sample 2#>Sample 4#>Sample 1#>Sample 3# Measuring initial viscosity Sample 3#>Sample 4#>Sample 1#>Sample 2# The method of the present invention Sample 4#>Sample 2#>Sample 3#>Sample 1#

[0062] The above predictions were compared with the actual conditions of samples stored at hot storage and long-term room temperature to determine the accuracy of predictions by different methods. Four groups of inorganic bismuth vanadate color paste samples were stored at 40°C for 14 days and room temperature samples were stored for 90 days. The sedimentation conditions are shown in Table 6 below.

[0063] Table 6 Stability of inorganic bismuth vanadate color paste samples 1#-4# during hot storage and long-term room temperature storage

[0064]

[0065] According to the results in Table 6, after the inorganic bismuth vanadate color paste samples 1#-4# were respectively subjected to heat storage and long-term room temperature storage, the stability order was sample 4#>sample 2#>sample 3#>sample 1#, which was consistent with the test results described in Example 1 of the present invention. It can be seen that in the parallel formulation screening, the method described in the present invention is more accurate than the traditional particle size method and viscosity method in predicting the long-term storage stability of color pastes of different formulations.

[0066] Example 2: Long-term storage stability test of organic phthalocyanine green slurry

[0067] A color paste based on phthalocyanine green pigment has a phenomenon of viscous aggregates after long-term storage (more than 3 months), and the viscous aggregates cannot be seen by visual inspection and cannot be accurately judged by traditional viscosity tests. This example conducts long-term storage stability testing on this type of organic phthalocyanine green paste.

[0068] Organic phthalocyanine green slurry samples 1#-4# were prepared according to the formula shown in Table 7, the steps comprising:

[0069] S1:

[0070] (1) Organic phthalocyanine green pulp samples 1#-4# were divided into two groups: RT and HS. The storage conditions of the RT group were room temperature storage (25°C), and the storage conditions of the HS group were high temperature storage (40°C). The storage time of both the RT and HS groups was 14 days.

[0071] (2) Samples 1#-4# of the RT and HS groups were dispersed by oscillation using a SK550 oscillator, with the oscillation program set to level II and the oscillation time of 10 min. After oscillation, the samples were allowed to stand for 60 min.

[0072] (3) The rheometer was set to the rotation mode, and samples 1#-4# of the RT and HS groups were processed after standing. The test fixture was CP-60, and the constant shear rate was 100 s -1 , time is 10s;

[0073] S2: The rheometer was set to the oscillation mode, and samples 1#-4# after RT and HS treatment were tested respectively, with a strain of 1.0%, a constant oscillation frequency of 0.1 Hz, and a time of 300 s to obtain the corresponding storage modulus G';

[0074] S3: Take G' in the test results as the ordinate and time t as the abscissa to draw a graph, and obtain the data analysis graph of the RT and HS groups of samples 1#-4#, as shown in Figure 2-Figure 5 As shown; define the rate of change α=Σ|(G HS '-G RT ') / G RT '|, calculate the change rate α of samples 1#-4# respectively, and the results are shown in Table 8.

[0075] Table 7 Formula of organic phthalocyanine green paste samples 1#-4#

[0076]

[0077] Table 8 Change rate of organic phthalocyanine green paste samples 1#-4#

[0078] Sample No. Rate of change α Sample 1# 605.7 Sample 2# 136.2 Sample 3# 259.8 Sample 4# 100.3

[0079] The smaller the change rate of the sample, the better the long-term storage stability. Therefore, it can be seen from Table 8 above that the long-term storage stability of organic phthalocyanine green paste samples 1#-4# is in the following order: sample 4#>sample 2#>sample 3#>sample 1#.

[0080] The actual storage stability of organic phthalocyanine green paste samples 1#-4# after being stored at high temperature (40°C) for 90 days is shown in Table 9 below.

[0081] Table 9 Storage stability of organic phthalocyanine green paste samples 1#-4#

[0082]

[0083] From the results in Table 9 above, it can be seen that after heat storage, the stability of organic phthalocyanine green paste samples 1#-4# is in the order of sample 4#>sample 2#>sample 3#>sample 1#, which is consistent with the test results described in this embodiment. It can be seen that the change rate α proposed in the present invention has a good correlation with the actual long-term storage stability of the color paste.

[0084] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A rheological method for quickly detecting the long-term storage stability of a color paste, characterized in that: The steps include: S1: using an oscillator to pre-treat the color paste to be tested, the pre-treating including but not limited to oscillating and dispersing the color paste to be tested; S2: Performing a rheological test using a rheometer; the rheological test includes but is not limited to measuring the storage modulus G' of the color paste to be tested using the rheometer in an oscillation mode; S3: Data processing and analysis.

2. The rheological method for rapid detection of long-term storage stability of color paste according to claim 1, characterized in that: The step S1 specifically comprises: using an oscillator to oscillate and disperse the color paste to be tested, and then letting it stand for 30 minutes to 120 minutes; The step S2 specifically includes: performing a linear viscoelastic region (LVR) measurement, adjusting the rheometer to an oscillation mode, and performing an amplitude sweep test on the color paste to be tested after standing, wherein the frequency range is set to 0.01-1.0 Hz, the strain range is set to 0-100%, and the storage modulus G' corresponding to different strains γ is obtained by testing; The step S3 is specifically as follows: plotting with G' as the ordinate and γ as the abscissa, taking the maximum γ corresponding to the linear region of G' max value, the value of G' is recorded as G' lin , defining the binding energy The larger the CE value, the better the long-term storage stability of the measured color paste.

3. The rheological method for rapid detection of long-term storage stability of color paste according to claim 2, characterized in that: In the step S1, before using an oscillator to oscillate and disperse the color paste to be tested, optionally, the step of storing the color paste to be tested at high temperature is also included; the high temperature is 40-60°C, preferably 50°C; the storage time is preferably 3-15 days, more preferably 5-10 days.

4. The rheological method for rapid detection of long-term storage stability of color paste according to claim 1, characterized in that: The step S1 specifically comprises: (1) dividing the color paste to be tested into two groups, RT and HS; wherein RT is a room temperature storage group, the storage temperature is 20-30°C, preferably 25°C; HS is a high temperature storage group, the storage temperature is 40-60°C, preferably 50°C; the storage time of the RT and HS groups is preferably 3-15 days, more preferably 7 days; (2) Using an oscillator, the two groups of RT and HS color pastes to be tested are shaken and dispersed respectively after storage, and then allowed to stand for 30 minutes to 120 minutes; (3) The rheometer was set to the rotation mode, and the RT and HS groups of color pastes were treated after standing, respectively. The constant shear rate was set in the range of 10-3000s. -1 , the processing time is 8-12s, preferably 10s; The step S2 specifically includes: adjusting the rheometer to an oscillation mode, testing the color pastes to be tested after the RT and HS treatments respectively, setting the strain interval to 0.1%-10%, the constant oscillation frequency setting interval to 0.01-1.0 Hz, and the test time to 250-350 s, preferably 300 s, to obtain the corresponding storage modulus G'; The step S3 is specifically as follows: plotting with G' as the ordinate and time t as the abscissa, defining the rate of change α = Σ|(G HS '-G RT ') / G RT '|, the smaller the change rate α, the better the long-term storage stability of the measured color paste, where G HS ' is the storage modulus of the color paste stored at high temperature, G RT ' is the storage modulus of the color paste stored at room temperature.

5. The rheological method for rapidly detecting the long-term storage stability of a color paste according to any one of claims 1 to 4, characterized in that: The oscillator is preferably an oscillator of model SK550, and the oscillation dispersion time is preferably 5-20 minutes.

6. The rheological method for rapidly detecting the long-term storage stability of a color paste according to any one of claims 1 to 4, characterized in that: The rheometer is preferably a rheometer of model Anton paar MCR 301, and the test fixture in step S2 is preferably CP-60.

7. The rheological method for rapidly detecting the long-term storage stability of a color paste according to any one of claims 2 to 3, characterized in that: The frequency setting interval in step S2 is preferably 0.05-1.0 Hz, and more preferably, the frequency is 0.1 Hz.

8. The rheological method for rapid detection of long-term storage stability of color paste according to claim 4, characterized in that: The setting interval of the constant shear rate in step S1 is preferably 50-150s -1 More preferably, the constant shear rate is 100s -1 .

9. The rheological method for rapid detection of long-term storage stability of color paste according to claim 4, characterized in that: The strain range in step S2 is preferably set to 0.5-10%, and more preferably, the strain is 1.0%.

10. The rheological method for rapid detection of long-term storage stability of color paste according to claim 4, characterized in that: The setting interval of the constant oscillation frequency in step S2 is preferably 0.05-1.0 Hz, and more preferably, the constant oscillation frequency is 0.1 Hz.

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