Calcium pyrophosphate as well as preparation method and application thereof

Abstract

The invention belongs to calcium pyrophosphate, and discloses a preparation method and application of calcium pyrophosphate, the particle size of calcium pyrophosphate is 5-25 [mu] m, and the aperture is 1t; the specific surface area is 1t; and 30m < 2 > / g. Tests show that the calcium pyrophosphate provided by the invention ensures that the copper loss value is not higher than 15mg, the friction coefficient RDA is not higher than 119 + / -2.87, and the film cleaning rate PCR is not less than 126 + / -3.68. When the film cleaning agent is added into toothpaste, the copper consumption value of the obtained toothpaste is not higher than 12.3 mg, the friction coefficient RDA is 105 + / -2.18, meanwhile, the film cleaning rate PCR is 113 + / -3.22, and the prepared toothpaste has excellent stability. The calcium pyrophosphate provided by the invention is added into the toothpaste, so that the prepared toothpaste can effectively clean teeth, does not damage enamel of people, and protects tooth health.

Description

Technical Field

[0001] The invention relates to calcium pyrophosphate, and more specifically to pyrophosphoric acid and a preparation method and application thereof. Background Art

[0002] In the field of oral care, calcium pyrophosphate is often added to toothpaste as an abrasive. It not only has the function of rubbing and cleaning teeth, but also can provide calcium and phosphates needed to maintain dental health, which helps to build and repair teeth. However, the friction coefficient RDA (Rubbing Disc Apparatus coefficient of friction) of calcium pyrophosphate provided by the prior art is too high, which causes damage to tooth enamel, or the friction coefficient RDA of calcium pyrophosphate provided by the prior art is too low, which makes the film cleaning ratio PCR (Pellicle Cleaning Ratios) too low, resulting in insufficient tooth cleaning ability. Summary of the invention

[0003] In order to overcome the defects in the prior art, the present invention provides a calcium pyrophosphate which can clean teeth with low wear and high cleaning effect.

[0004] Another object of the present invention is to provide a method for preparing calcium pyrophosphate, which can prepare the calcium pyrophosphate provided by the present invention.

[0005] Another object of the present invention is to provide the use of the calcium pyrophosphate in toothpaste.

[0006] The larger the particle size of calcium pyrophosphate and the lower the specific surface area BET, the stronger its cleaning ability is, but the more serious the wear on tooth enamel is. Therefore, increasing the specific surface area of ​​calcium pyrophosphate can reduce its wear value, but the cleaning ability will also be reduced accordingly.

[0007] In order to solve the above technical problems, the technical solution provided by the present invention is:

[0008] A calcium pyrophosphate having a particle size D50 of 5 to 25 μm, a pore size of <30 nm, and a specific surface area of ​​<30 m 2 / g.

[0009] The calcium pyrophosphate provided by the present invention has a particle size, pore size and specific surface area within a specific range. According to tests, the calcium pyrophosphate provided by the present invention has a copper loss value of no more than 15.3 mg, a friction coefficient RDA of no more than 119±2.87, and a film cleaning rate PCR of no less than 126±3.68. The calcium pyrophosphate provided by the present invention has the technical effect of low wear and high cleaning.

[0010] Preferably, the particle size of the calcium pyrophosphate is 10 to 20 μm.

[0011] Preferably, the calcium pyrophosphate has a specific surface area of ​​<20 m 2 / g.

[0012] Preferably, the pore volume of the calcium pyrophosphate is 10 to 120 mm 3 .

[0013] Preferably, the pore volume of the calcium pyrophosphate is 40 to 100 mm 3 .

[0014] Preferably, the calcium pyrophosphate pore size is 10 to 25 nm.

[0015] To produce the particle size D50 provided by the present invention with a particle size of 5 to 25 μm, a pore size of <30 nm, and a specific surface area of ​​<30 m 2 / g of the above calcium pyrophosphate has the following difficulties:

[0016] (1) As is well known, the higher the calcination temperature of calcium carbonate, the smaller the specific surface area of ​​the obtained calcium pyrophosphate and the larger the pore size. Therefore, if the calcination temperature of calcium carbonate is increased during the preparation of calcium pyrophosphate, the final obtained calcium pyrophosphate has a small specific surface area but a large particle size. Large particles of calcium pyrophosphate are added to toothpaste as an abrasive, which causes serious wear on teeth.

[0017] (2) As we all know, when calcium carbonate is calcined and water is added to generate a solution that reacts with phosphoric acid, if the temperature is too low or the phosphoric acid concentration is too low, the surface of the calcium pyrophosphate produced will be loose and porous, and the cleaning power will be relatively poor;

[0018] (3) As is known to all, if the intermediate product generated in (2) is calcined at a too high temperature, the resulting calcium pyrophosphate will have a small specific surface area, but a relatively small pore volume and a relatively large pore size. When added to toothpaste as an abrasive, it will have a high abrasive capacity. If the intermediate product is calcined at a too low temperature, the resulting calcium pyrophosphate will have a relatively large specific surface area, but a relatively small pore size. When added to toothpaste as an abrasive, it will not have sufficient teeth cleaning ability.

[0019] To this end, the present invention provides a method for preparing calcium pyrophosphate, comprising the following steps:

[0020] S1. Calcine carbonate is calcined and water is added to form a solution;

[0021] S2. The solution reacts with phosphoric acid to generate an intermediate product;

[0022] S3. calcining the intermediate product to obtain calcium pyrophosphate;

[0023] S2 specifically: firstly heat the solution to 80°C, then continuously add phosphoric acid to react until the pH value of the solution reaches 6.8-7.2, then stop adding phosphoric acid, the reaction is finished, and filter to obtain the intermediate product;

[0024] The calcination temperature in S3 is 400-800°C.

[0025] The preparation method provided by the present invention comprises the following steps: the reaction temperature of the calcium hydroxide obtained in S2 and the phosphoric acid is 80°C; the calcination temperature of the intermediate product in S3 is 400-800°C; and it has been verified by experiments that the combination of steps S1-S3 can produce the nanostructured carbon nanotubes provided by the present invention with a particle size of 5-25 μm, a pore size of <30 nm, and a specific surface area of ​​<30 m 2 / g of calcium pyrophosphate.

[0026] Preferably, the calcination temperature in S1 is 800-1000°C.

[0027] The specific steps of S3 of the present invention are: calcining the intermediate product obtained in S2 at 400-800° C., cooling and crushing the intermediate product to obtain calcium pyrophosphate.

[0028] S3. The calcination temperature is 500-700°C.

[0029] Preferably, the S3 intermediate product is calcined for 1 to 4 hours.

[0030] The phosphoric acid in S2 of the present invention is added in the form of a solution, the concentration of the phosphoric acid solution is 0.25-1.5 mol / L, and the addition rate of the phosphoric acid solution is 15-25 L / h.

[0031] The filtration process in S2 of the present invention is specifically as follows: after the reaction is completed, the solution is allowed to settle, the supernatant in the stratification is discarded, and the precipitate is retained and squeezed by a filter press to achieve solid-liquid separation.

[0032] The cooling process in S3 of the present invention is specifically to cool naturally to room temperature; the pulverizing process is specifically to use a ball mill for pulverizing.

[0033] The present invention also provides a toothpaste, the components of which include the calcium pyrophosphate.

[0034] Preferably, the calcium pyrophosphate added to the toothpaste is 5 to 45 wt%.

[0035] More preferably, 0.1-1 wt% of a fluorine-containing compound is further added to the toothpaste, wherein the fluorine-containing compound is selected from one or both of sodium monofluorophosphate and fluoride.

[0036] The calcium pyrophosphate contained in the toothpaste of the present invention has a pore size, a specific surface area and a particle size within a reasonable range. The toothpaste ensures that the copper loss value is not higher than 12.3 mg, the friction coefficient RDA is 105±2.18 and the film cleaning rate PCR is 113±3.22. Therefore, the toothpaste can clean teeth with high cleaning and low wear, and is more conducive to the fluoride compound in the toothpaste to play a role and prevent the occurrence of caries. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A microscopic morphology of calcium pyrophosphate is provided for Example 1.

[0038] Figure 2 A microscopic morphology of calcium pyrophosphate is provided for Comparative Example 3.

[0039] Figure 3 It is the infrared spectrum of calcined calcium pyrophosphate of Example 1. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below in conjunction with specific implementation methods.

[0041] Example 1

[0042] A calcium pyrophosphate particle size D50 is 15.61 μm, pore size is 18.0 nm, and specific surface area BET is 16 m 2 / g, pore volume 72.0mm 3 .

[0043] The preparation method of the calcium pyrophosphate comprises the following steps:

[0044] S1. Calcium carbonate is calcined at 1000°C for 12h to obtain a powder, and water is added to the powder to generate a solution; the mass ratio of the powder to water is 1:2;

[0045] S2. First, heat the solution to 80°C, then add phosphoric acid. When the pH value of the solution is 6.8-7.2, the reaction is completed and the intermediate product is obtained by filtration. The concentration of the phosphoric acid solution is 1 mol / L. The phosphoric acid solution is added at a rate of 20 L / h.

[0046] S3. The intermediate product was calcined at 600° C. for 2 h, naturally cooled to room temperature, put into a ball mill, and crushed for 45 min. The material was taken out to obtain calcium pyrophosphate with a particle size D50 of 15.61 μm.

[0047] Example 2

[0048] This embodiment is the second embodiment of the present invention. The difference from the first embodiment is that the particle size D50 of calcium pyrophosphate is 5.13 μm.

[0049] In the preparation method of calcium pyrophosphate, the S3 ball milling time is 90 minutes.

[0050] Example 3

[0051] This embodiment is the third embodiment of the present invention. Different from the first embodiment, the particle size D50 of calcium pyrophosphate is 24.98 μm.

[0052] In the preparation method of calcium pyrophosphate, the S3 ball milling time is 20 minutes.

[0053] Example 4

[0054] This embodiment is the fourth embodiment of the present invention. Different from the first embodiment, the particle size D50 of calcium pyrophosphate is 10.17 μm.

[0055] In the preparation method of calcium pyrophosphate, the S3 ball milling time is 60 minutes.

[0056] Example 5

[0057] This embodiment is the fourth embodiment of the present invention. Different from the first embodiment, the particle size D50 of calcium pyrophosphate is 20.21 μm.

[0058] In the preparation method of calcium pyrophosphate, the S3 ball milling time is 25 minutes.

[0059] Example 6

[0060] This embodiment is the sixth embodiment of the present invention. The difference from the first embodiment is that the particle size D50 of calcium pyrophosphate is 15.42 μm, the pore size is 10.01 nm, and the specific surface area BET is 16.3 m 2 / g, pore volume 40.8mm 3 .

[0061] The preparation method of calcium pyrophosphate is different from the preparation method of Example 1 in that:

[0062] S2. The phosphoric acid solution was added at a rate of 15 L / h;

[0063] S3. The calcination process is: the intermediate product is calcined at 700°C for 2h.

[0064] Example 7

[0065] This embodiment is the seventh embodiment of the present invention. The difference from the first embodiment is that the particle size D50 of calcium pyrophosphate is 15.75 μm, the pore size is 24.5 nm, and the specific surface area BET is 15.7 m 2 / g, pore volume 96.2mm 3 .

[0066] The preparation method of calcium pyrophosphate is different from the preparation method of Example 1 in that:

[0067] S2. The phosphoric acid solution is added at a rate of 20 L / h;

[0068] S3. The calcination process is: the intermediate product is calcined at 700°C for 3h.

[0069] Example 8

[0070] This embodiment is the eighth embodiment of the present invention. The difference from the first embodiment is that the particle size D50 of calcium pyrophosphate is 16.01 μm, the pore size is 29.45 nm, and the specific surface area BET is 15.37 m 2 / g, pore volume 113.16mm 3 .

[0071] The preparation method of calcium pyrophosphate is different from the preparation method of Example 1 in that:

[0072] S2. The phosphoric acid solution was added at a rate of 25 L / h;

[0073] S3. The calcination process is: the intermediate product is calcined at 700°C for 4 hours.

[0074] Example 9

[0075] This embodiment is the ninth embodiment of the present invention. The difference from the first embodiment is that the particle size D50 of calcium pyrophosphate is 15.73 μm, the pore size is 17.42 nm, and the specific surface area BET is 9.5 m 2 / g, pore volume 41.4mm 3 .

[0076] The preparation method of calcium pyrophosphate is different from the preparation method of Example 1 in that:

[0077] S2. The concentration of phosphoric acid solution is 0.8 mol / L;

[0078] S3. The calcination process is: the intermediate product is calcined at 700°C for 2h.

[0079] Example 10

[0080] This embodiment is the tenth embodiment of the present invention. The difference from the first embodiment is that the particle size D50 of calcium pyrophosphate is 15.44 μm, the pore size is 29.58 nm, and the specific surface area BET is 13.5 m 2 / g, pore volume 99.8mm 3 .

[0081] The preparation method of calcium pyrophosphate is different from the preparation method of Example 1 in that:

[0082] S2. The concentration of phosphoric acid solution is 1.2 mol / L;

[0083] S3. The calcination process is: the intermediate product is calcined at 500°C for 2h.

[0084] Embodiment 11

[0085] This embodiment is the 11th embodiment of the present invention. The difference from the first embodiment is that the particle size D50 of calcium pyrophosphate is 14.89 μm, the pore size is 8.2 nm, and the specific surface area BET is 5 m 2 / g, pore volume 10.3mm 3 .

[0086] The preparation method of calcium pyrophosphate is different from the preparation method of Example 1 in that:

[0087] S2. The concentration of phosphoric acid solution is 0.25 mol / L;

[0088] S3. The calcination process is: the intermediate product is calcined at 800°C for 2h.

[0089] Example 12

[0090] This embodiment is the twelfth embodiment of the present invention. The difference from the first embodiment is that the particle size D50 of calcium pyrophosphate is 15.77 μm, the pore size is 17.9 nm, and the specific surface area BET is 26.9 m 2 / g, pore volume 120.4mm 3 .

[0091] The preparation method of calcium pyrophosphate is different from the preparation method of Example 1 in that:

[0092] S2. The concentration of phosphoric acid solution is 1.5 mol / L;

[0093] S3. The calcination process is: the intermediate product is calcined at 400°C for 2h.

[0094] Embodiment 13

[0095] This embodiment is the 13th embodiment of the present invention. The difference from the first embodiment is that the particle size D50 of calcium pyrophosphate is 16.21 μm, the pore size is 16.9 nm, and the specific surface area BET is 20.3 m 2 / g, pore volume 85.8mm 3 .

[0096] The preparation method of calcium pyrophosphate is different from the preparation method of Example 1 in that:

[0097] S1. The calcium carbonate calcination process is: calcination at 900℃ for 12h;

[0098] S3. The calcination process is: the intermediate product is calcined at 600°C for 3h.

[0099] Embodiment 14

[0100] This embodiment is the 14th embodiment of the present invention. The difference from the first embodiment is that the particle size D50 of calcium pyrophosphate is 15.75 μm, the pore size is 15.8 nm, and the specific surface area BET is 30.08 m 2 / g, pore volume 118.9mm 3 .

[0101] The preparation method of calcium pyrophosphate is different from the preparation method of Example 1 in that:

[0102] S1. Calcium carbonate calcination process is: calcination at 800℃ for 12h

[0103] S3. The calcination process is: the intermediate product is calcined at 400°C for 1 hour.

[0104] Comparative Example 1

[0105] This comparative example is the first comparative example of the present invention, and is different from Example 1 in that the particle size D50 of calcium pyrophosphate is 3.15 μm. In the preparation method of calcium pyrophosphate, the S3 ball milling time is 100 min.

[0106] Comparative Example 2

[0107] This comparative example is the second comparative example of the present invention, and is different from Example 1 in that the particle size D50 of calcium pyrophosphate is 30.59 μm. In the preparation method of calcium pyrophosphate, the S3 ball milling time is 10 min.

[0108] Comparative Example 3

[0109] This comparative example is the third comparative example of the present invention. The difference from Example 1 is that the particle size D50 of calcium pyrophosphate is 15.79 μm, the pore size is 35.78 nm, and the specific surface area BET is 20.2 m 2 / g, pore volume 180.7mm 3 .

[0110] The preparation method of calcium pyrophosphate is different from the preparation method of Example 1 in that:

[0111] S2. The phosphoric acid solution was added at a rate of 35 L / h;

[0112] S3. The calcination process is: the intermediate product is calcined at 300°C for 3h.

[0113] Comparative Example 4

[0114] This comparative example is the fourth comparative example of the present invention. The difference from Example 1 is that the particle size D50 of calcium pyrophosphate is 15.24 μm, the pore size is 34.2 nm, and the specific surface area BET is 15.1 m 2 / g, pore volume 129.1mm 3 .

[0115] The preparation method of calcium pyrophosphate is different from the preparation method of Example 1 in that:

[0116] S2. The concentration of phosphoric acid solution is 0.15 mol / L;

[0117] S3. The calcination process is: the intermediate product is calcined at 300°C for 3h.

[0118] Comparative Example 5

[0119] This comparative example is the fifth comparative example of the present invention. The difference from Example 1 is that the particle size D50 of calcium pyrophosphate is 16.07 μm, the pore size is 13.92 nm, and the specific surface area BET is 2.3 m 2 / g, pore volume 8.0mm 3 .

[0120] The preparation method of calcium pyrophosphate is different from the preparation method of Example 1 in that:

[0121] S2. The concentration of phosphoric acid solution is 2.0 mol / L;

[0122] S3. The calcination process is: the intermediate product is calcined at 900°C for 2h.

[0123] Comparative Example 6

[0124] This comparative example is the sixth comparative example of the present invention. The difference from Example 1 is that the particle size D50 of calcium pyrophosphate is 14.95 μm, the pore size is 20.2 nm, and the specific surface area BET is 35.78 m 2 / g, pore volume 180.6mm 3 .

[0125] The preparation method of calcium pyrophosphate is different from the preparation method of Example 1 in that:

[0126] S1. Calcium carbonate calcination process is: calcination at 600℃ for 12h

[0127] S3. The calcination process is: the intermediate product is calcined at 300°C for 1 hour.

[0128] Performance testing:

[0129] Copper loss detection method: (1) Take 2 copper sheets, clean them with distilled water, blow dry them with a hair dryer, place them in a dryer for 15 minutes, then take out the copper sheets with tweezers, weigh the weight W1 (in mg) of the two copper sheets before wear respectively, and place the copper sheets in the material trough of the hard particle counter after weighing; (2) Accurately weigh 20g of calcium pyrophosphate obtained in any embodiment or comparative example, evenly disperse it in 120g of sorbitol solution, transfer the obtained friction particle slurry to the material trough of the hard particle counter, turn on the hard particle counter, and make the friction head rub the copper sheet continuously for 10,000 times in the test slurry. After the friction is completed, take out the copper sheet with tweezers, rinse it with distilled water, blow it dry with a hair dryer, place it in a dryer for 15 minutes, take out the copper sheet with tweezers and weigh its weight after wear W2 (in mg); (3) Copper wear value W = W1-W2 (in mg), the deviation of parallel experimental results cannot exceed 20%, and the average value is taken as the final result. The test results of copper loss of calcium pyrophosphate obtained in the embodiment and comparative example are shown in Table 1.

[0130] Surface roughness Ra test: The test was conducted according to the national standard GBT35832-2018 toothpaste friction value detection method. The specific test method is as follows: (1) 10 g CMC was dissolved in 200 mL glycerol, and the volume was adjusted to 2000 mL with deionized water and placed for 12 hours for use; (2) 260 g of calcium pyrophosphate obtained in any embodiment or comparative example was weighed and added to 1300 mL of the above dilution solution and stirred for 2 hours for use; (3) PMMA abrasive blocks (8 blocks / group), toothbrushes and slurry cups were installed on the brush grinding instrument. Inject deionized water into the slurry cup until the PMMA module is buried, brush and grind with a pressure of 200±2g, and brush and grind 200 times at a speed of 100 times / min; (4) After the pre-brushing is completed, remove the deionized water in the slurry cup, inject the prepared toothpaste slurry into each slurry cup until the PMMA grinding block is buried, and fine-tune the pressure of the brush grinder to 200±2g, and brush and grind 8000 times at a speed of 100 times / min. It is divided into 4 rounds, each 2000 times. After each round, remove the slurry cup and stir it and continue the test; (5) After the test, remove the toothbrush and module, clean the module and dry it, take 7 scanning areas in the middle area with the most dense scratches, and test the Ra value with a surface roughness meter, and then take the average value of the 7 points as the Ra value of the sample. The test results of calcium pyrophosphate RDA obtained in the embodiment and comparative example are shown in Table 1.

[0131] Cleaning ability test: The test method of PCR (Pellicle Cleaning Ratios) is as follows:

[0132] Enamel specimens were obtained by cutting off the permanent central incisors of cattle, and the enamel specimens were embedded in methyl methacrylate resin. The enamel surface was polished by a grinder and polisher in a continuously flowing water. The polished specimens were then treated with hydrochloric acid, sodium carbonate, and phytic acid, respectively. The enamel specimens were attached to a staining device that alternately immersed the enamel specimens in the staining solution and then air-dried at a speed of 1 revolution per minute. The staining time of the specimens lasted for about 7 days, and the staining solution was changed every two days. The stained specimens were evaluated for tooth color using a colorimeter, and 30<L*<40 was a qualified baseline enamel specimen. The stained enamel specimens were scrubbed 400 times on a scrubber using 150 grams of standard calcium pyrophosphate suspension and test abrasive slurry. The L* value of the enamel after scrubbing was measured using a colorimeter, and then the film cleaning rate (PCR) can be calculated as follows:

[0133]

[0134] Wherein: ΔL=Lafter polishing-Lbaseline; the test sample is the calcium pyrophosphate obtained in any embodiment or comparative example.

[0135] The PCR test results of calcium pyrophosphate obtained in the embodiment and the comparative example are shown in Table 1. The copper consumption value of calcium pyrophosphate obtained in the embodiment is 15.3 mg, the RDA is 119±2.87, and the cleaning performance is 126±3.68. The calcium pyrophosphate obtained in the embodiment can achieve low copper consumption value and low RDA while maintaining high cleaning performance PCR, which is better than the comparative example.

[0136] As can be seen from Table 1, the particle size of Example 1 and calcium pyrophosphate

[0137] Table 1 Examples and Comparative Examples provide calcium pyrophosphate performance tests

[0138]

[0139] Example 1 provides a scanning electron microscope of calcium pyrophosphate Figure 1 The microscopic morphology of the calcium pyrophosphate obtained in the other examples is similar Figure 1 Comparative Example 3 provides a scanning electron microscope of calcium pyrophosphate. Figure 2 . Figure 1 The shape of medium calcium pyrophosphate is irregular and the surface is relatively dense. Figure 2 It can be seen that the calcium pyrophosphate product provided in Comparative Example 3 has a loose and porous surface. The calcium pyrophosphate product with a dense internal structure has a higher friction value and better cleaning ability than the product with a loose surface during the application stage.

[0140] Compared with the comparative example, the calcium pyrophosphate obtained in the embodiment has uniform particle size, narrow particle size distribution, and small particle size dispersion PDI. When added into toothpaste as an abrasive, the toothpaste has small RDA wear on teeth and high cleaning power PCR.

[0141] Infrared spectrum test: The infrared spectrum test of calcium pyrophosphate obtained in the embodiment was carried out using a DTGS detector, and the test range was: 4000~400cm -1 , scanning times 32 times, resolution 2cm -1 The infrared spectrum of calcium pyrophosphate obtained in Example 1 is shown in Figure 3 The molecular formula of calcium pyrophosphate is Ca 2 P 2 O 7 ,from Figure 2 In the infrared spectrum, it can be observed at 1200cm -1 Up to 400cm -1 Wave number band, appears Vibration peaks at 973, 939 and 722 cm -1 The POP vibration peaks appear, and the characteristic peaks between 1200-1000 and 600-400 are attributed to Vibration. The infrared spectra of calcium pyrophosphate obtained in the other embodiments are similar Figure 2 .

[0142] Application Examples

[0143] A toothpaste, the formula components are as follows: 27% calcium pyrophosphate, 13% silicon dioxide, 37% glycerol, 2.5% disodium stearoylamphodiacetate, 2% sodium carboxymethylcellulose, 0.15% preservative, 0.5% sodium monofluorophosphate, and the balance is water, wherein the calcium pyrophosphate is the calcium pyrophosphate obtained in the examples and comparative examples.

[0144] Performance Testing

[0145] The copper loss, Ra, and PCR test methods are the same as those for the calcium pyrophosphate obtained in the examples and comparative examples. The test results of the abrasion cleaning performance of toothpaste prepared using the calcium pyrophosphate provided in the examples and comparative examples are shown in Table 2.

[0146] The calcium pyrophosphate obtained in the embodiment is added to the toothpaste to achieve low copper loss value and low RDA for teeth while maintaining high cleaning performance PCR, which is better than the comparative example.

[0147] Table 2 Examples and Comparative Examples provide toothpaste made from calcium pyrophosphate with abrasion and cleaning performance test

[0148]

[0149]

[0150] Stability performance test: Use a viscometer to test the viscosity of the toothpaste. Record the test temperature while testing the viscosity data. Observe the changes in the paste from time to time to see if there is any water separation, yellowing, or coarsening.

[0151] The toothpaste made of calcium pyrophosphate provided by the present invention was left to stand for one week, one month, and three months at low temperature -10°C, room temperature, and high temperature 40°C. The viscosity of the toothpaste did not change much, and the paste did not separate, turn yellow, or become rough. The stability test results of the toothpaste made of calcium pyrophosphate provided in the embodiment are shown in Table 3.

[0152] Table 3 Examples and Comparative Examples provide toothpaste stability test of calcium pyrophosphate

[0153]

[0154]

[0155] Note: The unit of viscosity is centipoise (cp). The unit used in this table is ten thousand centipoise (wcp), that is, 1wcp = 10000 centipoise.

[0156] In summary, the specific surface area, particle size and pore size of calcium pyrophosphate provided by the present invention are within a certain range, and the calcium pyrophosphate has the technical effect of low wear and high wear at the same time. The performance is stable when added to toothpaste, and the calcium pyrophosphate can clean teeth while protecting the health of tooth enamel.

[0157] The above is only an implementation method of the invention, and does not limit the scope of patent protection. Those skilled in the art can make non-substantial changes or substitutions based on the invention, which still fall within the scope of patent protection.

Claims

1. A calcium pyrophosphate, characterized in that Particle size D50 is 5-25μm, pore size <30nm, specific surface area <30m 2 / g.

2. Calcium pyrophosphate according to claim 1, characterized in that, The specific surface area of ​​calcium pyrophosphate is less than 20 m 2 / g.

3. Calcium pyrophosphate according to claim 1, characterized in that The pore volume of calcium pyrophosphate is 10 to 120 mm 3 .

4. Calcium pyrophosphate according to claim 3, characterized in that, The pore volume of calcium pyrophosphate is 40 to 100 mm 3 .

5. Calcium pyrophosphate according to claim 1, characterized in that, The calcium pyrophosphate pore diameter is 10 to 25 nm.

6. A method for preparing calcium pyrophosphate according to any one of claims 1 to 5, comprising the following steps: S1. Calcine carbonate is calcined and water is added to form a solution; S2. The solution reacts with phosphoric acid to generate an intermediate product; S3. calcining the intermediate product to obtain calcium pyrophosphate; It is characterized in that S2 specifically: firstly heat the solution to 80°C, then continuously add phosphoric acid to react until the pH value of the solution reaches 6.8-7.2, then stop adding phosphoric acid, the reaction is finished, and filter to obtain the intermediate product; The calcination temperature in S3 is 400-800°C.

7. The method for preparing calcium pyrophosphate according to claim 6, wherein The calcination temperature in S1 is 800-1000°C.

8. The method for preparing calcium pyrophosphate according to claim 6, wherein: The calcination temperature in S3 is 500-700°C.

9. A toothpaste, characterized in that: The toothpaste component comprises the calcium pyrophosphate according to any one of claims 1 to 5.

10. The toothpaste according to claim 9, characterized in that: The added amount of calcium pyrophosphate is 5 to 45 wt%.

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