A high thixotropic easily dispersible hec particle for toothpaste, a method of preparation and use

Abstract

This invention discloses a highly thixotropic and easily dispersible HEC particle for toothpaste, its preparation method, and its applications, belonging to the field of hydroxyethyl cellulose ether preparation technology. The specific process involves using hydroxyethyl cellulose ether as the core material, and then spray-granulating and coating it with a granulation solution containing an organic thickener and water-soluble polyol additives. This invention uses hydroxyethyl cellulose ether as the core material and employs a fluidized bed spray granulation method, utilizing an aqueous granulation solution containing organic thickeners and water-soluble polyol additives to simultaneously bind, granulate, and surface-coat hydroxyethyl cellulose powder, thereby resulting in particles that simultaneously possess good water dispersibility and high thixotropic properties. The obtained product has almost no core coating and disperses rapidly; simultaneously, the thixotropic values ​​of multiple optimized systems reach or exceed the levels of similar products on the market.

Description

Technical Field

[0001] This invention belongs to the field of hydroxyethyl cellulose ether preparation technology, specifically relating to a highly thixotropic and easily dispersible HEC particle for toothpaste, its preparation method, and its uses. Background Technology

[0002] Hydroxyethyl cellulose ether (HEC) is a commonly used nonionic water-soluble cellulose ether that functions as a thickener, water retainer, suspender, and rheology modifier in toothpaste systems. For general-purpose toothpastes, in addition to having a suitable base viscosity, good dispersibility and thixotropic properties are also necessary to ensure structural stability of the paste in a static state and good flowability and structural recovery during extrusion and brushing.

[0003] However, HEC for toothpaste generally has two problems in practical applications: First, the powder tends to agglomerate and core after being added to water, affecting the dispersion speed and system uniformity; second, simply improving the thixotropic properties of the system is often accompanied by a significant increase in viscosity, resulting in a thicker paste and increased extrusion resistance, which affects the actual user experience.

[0004] In existing technologies, one approach improves rheological properties by modifying the bulk structure of cellulose ethers. For example, patent CN101171264B discloses low-substituted hydroxyethyl cellulose and its derivatives, emphasizing their good thickening efficiency and rheological properties. Another approach focuses on the thickening and stability adjustment of the toothpaste formulation itself. For instance, patents CN113827508A and CN110478269A improve upon these aspects from the perspectives of thickener blending and viscosity stability in high-salt toothpaste, respectively. While these technologies offer valuable insights for improving the rheological performance of toothpaste systems, they primarily focus on bulk modification of cellulose ethers or toothpaste formulation adjustments. They do not address the problems of HEC powder in toothpaste, such as easy core-coating during water dispersion and the difficulty in simultaneously achieving high thixotropy. Therefore, existing technologies do not offer a solution that simultaneously improves the dispersibility and thixotropic properties of HEC in toothpaste. Summary of the Invention

[0005] To address the aforementioned shortcomings in the prior art, this invention provides a highly thixotropic and easily dispersible HEC particle for toothpaste, its preparation method, and its application, thereby solving the problems of insufficient dispersibility, easy core encapsulation, and excessively high viscosity after simply increasing thixotropy in existing HEC systems for toothpaste.

[0006] To achieve the above objectives, the technical solution adopted by the present invention to solve its technical problem is as follows: The purpose of this invention is to provide a method for preparing highly thixotropic and easily dispersible hydroxyethyl cellulose ether particles for toothpaste. The method uses hydroxyethyl cellulose ether as the core material and is obtained through spray granulation and coating treatment with a granulation solution containing an organic thickener and a water-soluble polyol additive. After granulation, the organic thickener and the water-soluble polyol additive are mainly distributed on the particle surface and can partially penetrate into the near-surface or interior of the particles during the granulation process, thereby giving the resulting particles both good dispersibility and high thixotropic properties.

[0007] Furthermore, in the granulation solution, the amount of water-soluble polyol auxiliaries is 1-15% of the mass of hydroxyethyl cellulose ether; The mass concentration of the organic thickener in the granulation solution is 0.1~3.0%.

[0008] Furthermore, in the granulation solution, the amount of water-soluble polyol auxiliaries is 3-10% of the mass of hydroxyethyl cellulose ether.

[0009] Furthermore, in the granulation solution, the amount of water-soluble polyol auxiliaries is 5-8% of the mass of hydroxyethyl cellulose ether.

[0010] Furthermore, the mass concentration of the organic thickener in the granulation solution is 0.5~2.0%.

[0011] Furthermore, the mass concentration of the organic thickener in the granulation solution is 1.0%.

[0012] Furthermore, the water-soluble polyol additives are selected from one or more of polyethylene glycols, polyols, and sugar alcohols.

[0013] Furthermore, the organic thickener is selected from one or more of the following: natural polysaccharide thickeners, modified natural polysaccharide thickeners, water-soluble cellulose ether thickeners, and water-soluble natural or semi-synthetic polymeric thickeners.

[0014] Furthermore, the organic thickener is selected from one or more of xanthan gum, transparent xanthan gum, modified xanthan gum, guar gum, hydroxypropyl guar gum, locust bean gum, gellan gum, alginate, sodium carboxymethyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, ethyl hydroxyethyl cellulose, microcrystalline cellulose gum, and carbomer.

[0015] Furthermore, the particle size of the hydroxyethyl cellulose ether particles is 100~500 μm, and its specific distribution is as follows: D10 is 30~80 μm, D50 is 80~220 μm, and D90 is not higher than 350 μm.

[0016] Furthermore, the particle size of the hydroxyethyl cellulose ether particles is 180~380 μm.

[0017] Furthermore, the particle size of the hydroxyethyl cellulose ether particles is 200~300 μm.

[0018] The research of this invention shows that the proportion of fine powder, the bulk particle size, and the tail peak of coarse particles all affect the dispersion and thixotropic properties of the particles. When there is an excessive amount of fine powder in the particles, rapid surface hydration and core formation are likely to occur; while when the tail peak of coarse particles is too large, slow dispersion and coarsening of the paste are likely to occur. This invention, by reasonably controlling D10, D50, and D90, can achieve better dispersion and thixotropic properties in the obtained particles.

[0019] Furthermore, the specific treatment for granulation of the granulation liquid is as follows: atomization pressure 0.1~0.5 MPa; spray rate 1~5 rpm; inlet air temperature 50~70℃; material temperature 35~50℃; backflushing temperature 35~50℃; fan speed 800~1500 rpm; air volume 30~80 m³ / h. 3 / h.

[0020] Another object of the present invention is to provide highly thixotropic and easily dispersible hydroxyethyl cellulose ether particles for toothpaste, which are prepared by the above method.

[0021] Another object of the present invention is to provide the use of the above-mentioned highly thixotropic and easily dispersible hydroxyethyl cellulose ether particles for toothpaste in the preparation of a thickener for toothpaste or in the preparation of toothpaste.

[0022] Another object of the present invention is to provide a toothpaste comprising the above-described highly thixotropic and easily dispersible hydroxyethyl cellulose ether particles for toothpaste.

[0023] The beneficial effects of this invention are: This invention introduces organic thickeners and water-soluble polyol additives into the fluidized bed spray granulation process to simultaneously granulate and coat HEC powder, thereby improving particle dispersion performance, reducing core-coating tendency, and enhancing the thixotropic properties and structural recovery ability of the particle system.

[0024] This invention, through fluidized bed spray granulation and coating treatment, can obtain hydroxyethyl cellulose ether particle structures suitable for toothpaste applications, and can significantly improve dispersion and core-coating problems, especially in the particle size range of 200-300 μm.

[0025] This invention enables particles to simultaneously achieve good dispersion performance and high thixotropic properties by simultaneously introducing organic thickeners and water-soluble polyol additives into the granulation solution.

[0026] The thixotropic values ​​of some preferred embodiments of the present invention have reached or exceeded the levels of similar products on the market such as Dow and Aslan, while maintaining a suitable viscosity range.

[0027] The system of this invention is beneficial for improving the stiffness, structural recovery ability, and storage stability of toothpaste. The optimized sample meets the requirements in terms of paste appearance, consistency increase, stability, and suspension performance.

[0028] This invention is applicable to general toothpaste systems and has good application prospects. Attached Figure Description

[0029] Figure 1 The diagram shows a comparison of the dispersion properties of untreated and treated samples; where A represents the hydroxyethyl cellulose ether substrate without spray granulation and coating treatment, and B represents the hydroxyethyl cellulose ether particles prepared in Example 1 of this invention. Figure 2 The images show a comparison of SEM images of untreated and treated samples; where A is the hydroxyethyl cellulose ether substrate without spray granulation and coating treatment, and B is the hydroxyethyl cellulose ether particles prepared in Example 1 of this invention. Figure 3 This is a comparison chart of thixotropic values ​​for different particle system schemes. Detailed Implementation

[0030] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0031] Example 1 A highly thixotropic and easily dispersible hydroxyethyl cellulose ether particle for toothpaste is prepared by the following steps: (1) Take hydroxypropyl guar gum and sorbitol and prepare a uniform coating granulation solution in a liquid medium, wherein the mass concentration of hydroxypropyl guar gum in the coating granulation solution is 1.0% and the amount of sorbitol added based on the mass of hydroxyethyl cellulose ether substrate is 5.0%.

[0032] (2) Weigh 300 g of hydroxyethyl cellulose ether substrate and place it in a fluidized bed granulation device. Use 150 g of the granulation liquid as the spray liquid for granulation and coating. The granulation process control conditions are: atomization pressure 0.2 MPa, spray rate 2 rpm, inlet air temperature 60℃, material temperature 45℃, backflushing temperature 45℃, fan speed 1200 rpm, and air volume 50 m³ / h. 3 / h.

[0033] (3) After granulation, continue drying until the particle surface is no longer sticky, and obtain hydroxyethyl cellulose ether particles for toothpaste with high thixotropic dispersibility.

[0034] Example 2 A highly thixotropic and easily dispersible hydroxyethyl cellulose ether particle for toothpaste is prepared by the following steps: (1) Take hydroxypropyl guar gum and sorbitol and prepare a uniform coating granulation solution in a liquid medium, wherein the mass concentration of hydroxypropyl guar gum in the coating granulation solution is 1.0% and the amount of sorbitol added based on the mass of hydroxyethyl cellulose ether substrate is 8.0%.

[0035] (2) Weigh 300 g of hydroxyethyl cellulose ether substrate and place it in a fluidized bed granulation device. Use 150 g of the granulation liquid as the spray liquid for granulation and coating. The granulation process control conditions are: atomization pressure 0.2 MPa, spray rate 2 rpm, inlet air temperature 60℃, material temperature 45℃, backflushing temperature 45℃, fan speed 1200 rpm, and air volume 50 m³ / h. 3 / h.

[0036] (3) After granulation, continue drying until the particle surface is no longer sticky, and obtain hydroxyethyl cellulose ether particles for toothpaste with high thixotropic dispersibility.

[0037] Example 3 A highly thixotropic and easily dispersible hydroxyethyl cellulose ether particle for toothpaste is prepared by the following steps: (1) Take hydroxypropyl guar gum and sorbitol and prepare a uniform coating granulation solution in a liquid medium, wherein the mass concentration of hydroxypropyl guar gum in the coating granulation solution is 0.5% and the amount of sorbitol added based on the mass of hydroxyethyl cellulose ether substrate is 5.0%.

[0038] (2) Weigh 300 g of hydroxyethyl cellulose ether substrate and place it in a fluidized bed granulation device. Use 150 g of the granulation liquid as the spray liquid for granulation and coating. The granulation process control conditions are: atomization pressure 0.2 MPa, spray rate 2 rpm, inlet air temperature 60℃, material temperature 45℃, backflushing temperature 45℃, fan speed 1200 rpm, and air volume 50 m³ / h. 3 / h.

[0039] (3) After granulation, continue drying until the particle surface is no longer sticky, and obtain hydroxyethyl cellulose ether particles for toothpaste with high thixotropic dispersibility.

[0040] Example 4 A highly thixotropic and easily dispersible hydroxyethyl cellulose ether particle for toothpaste is prepared by the following steps: (1) Guar gum and sorbitol are prepared into a uniform coating granulation solution in a liquid medium, wherein the mass concentration of guar gum in the coating granulation solution is 0.5% and the amount of sorbitol added is 5.0% based on the mass of hydroxyethyl cellulose ether substrate.

[0041] (2) Weigh 300 g of hydroxyethyl cellulose ether substrate and place it in a fluidized bed granulation device. Use 150 g of the granulation liquid as the spray liquid for granulation and coating. The granulation process control conditions are: atomization pressure 0.2 MPa, spray rate 2 rpm, inlet air temperature 60℃, material temperature 45℃, backflushing temperature 45℃, fan speed 1200 rpm, and air volume 50 m³ / h. 3 / h.

[0042] (3) After granulation, continue drying until the particle surface is no longer sticky, and obtain hydroxyethyl cellulose ether particles for toothpaste with high thixotropic dispersibility.

[0043] Comparative Example 1 Compared with Example 1, only hydroxyethyl cellulose ether substrate was used, and pure water was used for granulation under the same fluidized bed conditions. Hydroxypropyl guar gum and sorbitol were not added. The rest of the process was the same as in Example 1.

[0044] Comparative Example 2 The method of Example 1 was used, except that hydroxypropyl guar gum was not added, and only sorbitol was added; the rest of the process was the same as in Example 1.

[0045] Comparative Example 3 The method of Example 1 was used, except that sorbitol was not added and only hydroxypropyl guar gum was used for granulation. The rest of the process was the same as in Example 1.

[0046] Comparative Example 4 Without granulation, the hydroxyethyl cellulose ether substrate is directly mixed with guar gum in a conventional manner.

[0047] Comparative Example 5 By using only the high thixotropic enhancement route without granulation, the hydroxyethyl cellulose ether matrix is ​​directly mixed with guar gum and / or other components used for thixotropic enhancement in a set ratio, without spray granulation and coating treatment, to obtain a non-granulated high thixotropic enhancement system.

[0048] Test case 1. The particles obtained in Examples 1-4 and Comparative Examples 1-5 of this invention were added to water to form a 1% aqueous solution. The viscosity, thixotropic value, and dispersion were then measured. The results are shown in Table 1 and... Figure 1 , Figure 3 .

[0049] Table 1. Basic performance test results of the examples and comparative examples

[0050] As shown in Table 1, the particles obtained in Examples 1-4 of the present invention maintain a suitable viscosity range while having a significantly higher thixotropic value than Comparative Examples 1 and 2, and their dispersion performance is better than that of Comparative Example 3. This indicates that the fluidized bed granulation scheme of the present invention, which synergistically encapsulates organic thickener and water-soluble polyol additives, can simultaneously improve the dispersibility and thixotropic properties of hydroxyethyl cellulose ether particles.

[0051] In addition, such as Figure 2 As shown, after being treated by the present invention, hydroxyethyl cellulose ether changes from its original powder morphology to a distinct granular structure, and the surface morphology changes, indicating that spray granulation and coating treatment have effectively changed the morphology of hydroxyethyl cellulose ether particles.

[0052] 2. Toothpaste preparation performance test In this invention, the toothpaste application evaluation is conducted using a universal toothpaste formulation system. This universal toothpaste formulation, by weight percentage, comprises: 20%–50% humectant, 20%–60% abrasive, 0.5%–5% surfactant, 0.05%–1% sweetener, 0.05%–0.5% preservative, 0.1%–2% fragrance, 0.2%–3.0% thickening agent, with the balance being water and other conventionally acceptable toothpaste components.

[0053] The humectant is selected from one or more of glycerin, sorbitol, and propylene glycol, preferably sorbitol; the abrasive is selected from one or more of silica and calcium carbonate, preferably calcium carbonate; the surfactant is selected from one or more of lauryl sulfate salts and betaines, preferably betaines; the remaining excipients are conventionally acceptable components of toothpaste.

[0054] The thickening system is at least partially composed of the particles of the present invention. The amount of the particles of the present invention added to the toothpaste formulation is 0.2% to 2.0%, more preferably 0.3% to 1.5%. The thickening system may also contain other commonly used toothpaste thickening components, the amount of which is 0% to 2.0%, preferably 0.1% to 1.0%. Other thickening components may be selected from sodium carboxymethyl cellulose, xanthan gum, guar gum derivatives, carbomer, and combinations thereof, preferably xanthan gum.

[0055] The particles obtained in Examples 2 and 4 and Comparative Examples 1, 4, and 5 of this invention were added as thickening components to the above-mentioned general-purpose toothpaste formulation, respectively designated as Application Example 1, Application Example 2, and Application Comparative Examples 1-3. Their appearance, consistency, consistency increase, one-month viscosity, stability, and overall application suitability in the toothpaste were then evaluated to verify their actual performance in the toothpaste system. The paste viscosity was measured using a Brookfield DV2T viscometer with a Helipath support and a T-bar rotor (TE#95) at 5 rpm, and the results are shown in Table 2.

[0056] Table 2 Comparison of toothpaste application performance results

[0057] According to the test results in Table 2, the toothpaste prepared based on the particles prepared in Example 2 of this invention has a uniform and fine appearance, no obvious particles, good extrusion molding properties, and good stiffness retention after standing. Its consistency is 18 after three days, with a consistency increase of 6, and its viscosity is 352000 mPa·s after one month, showing good stability. The toothpaste prepared based on the particles prepared in Example 4 has a uniform appearance, no obvious color difference, rapid structure recovery, and good suspension properties. Its consistency is 21 after three days, with a consistency increase of 6, and its viscosity is 358000 mPa·s after one month, showing good stability.

[0058] In comparison, the toothpaste prepared based on the particles in Comparative Example 1 contained visible fine particles, exhibited moderate uniformity, and felt slightly discontinuous during extrusion. Its consistency was 15 after three days, with a consistency increase of 3, and its viscosity was 326000 mPa·s after one month, indicating moderate stability.

[0059] The toothpaste prepared from the particles in Comparative Example 4 showed acceptable initial thixotropic properties, but its uniformity and dispersibility were significantly inferior to those of the present invention, with some areas exhibiting a grainy texture. The consistency was 12 after three days, with a consistency increase of 3, and the viscosity was 328,000 mPa·s after one month, indicating moderate stability.

[0060] The toothpaste prepared from the particles in Comparative Example 5 has a relatively thick consistency, high extrusion resistance, and a heavy feel. Its consistency was 24 after three days, with a consistency increase of 9, and its viscosity was 516,000 mPa·s after one month. While stable, its applicability is poor.

[0061] The test results above show that the particles prepared based on the present invention have superior performance in general-purpose toothpaste. The pastes obtained in Application Examples 1 and 2 exhibit a uniform appearance with no significant color difference. Their consistency remained within the range of 12-24 after 3 days, with a 3-day increase in consistency greater than or equal to 3. Simultaneously, their suspension performance and stability were normal. The paste viscosity remained stable for one month, measured using a Brookfield viscometer with a Helipath support and a T-bar rotor (TE#95) at 5 rpm. This indicates that only the particles prepared based on the present invention can meet the application requirements of toothpaste.

[0062] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing highly thixotropic and easily dispersible hydroxyethyl cellulose ether particles for toothpaste, characterized in that, It is prepared by spray granulation and coating with hydroxyethyl cellulose ether as core material and granulation solution containing organic thickener and water-soluble polyol additive.

2. The preparation method according to claim 1, characterized in that, In the granulation solution, the amount of water-soluble polyol auxiliaries is 1-15% of the mass of hydroxyethyl cellulose ether; The mass concentration of the organic thickener in the granulation solution is 0.1~3.0%.

3. The preparation method according to claim 1 or 2, characterized in that, Water-soluble polyol additives are selected from one or more of polyethylene glycols, polyols, and sugar alcohols.

4. The preparation method according to claim 1 or 2, characterized in that, The organic thickener is selected from one or more of the following: natural polysaccharide thickeners, modified natural polysaccharide thickeners, water-soluble cellulose ether thickeners, and water-soluble natural or semi-synthetic polymeric thickeners.

5. The preparation method according to claim 4, characterized in that, The organic thickener is selected from one or more of xanthan gum, transparent xanthan gum, modified xanthan gum, guar gum, hydroxypropyl guar gum, locust bean gum, gellan gum, alginate, sodium carboxymethyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, ethyl hydroxyethyl cellulose, microcrystalline cellulose gum, and carbomer.

6. The preparation method according to claim 1, characterized in that, The particle size of hydroxyethyl cellulose ether particles is 100~500 μm, and its specific distribution is as follows: D10 is 30~80 μm, D50 is 80~220 μm, and D90 is not higher than 350 μm.

7. The preparation method according to claim 1, characterized in that, The specific treatment for granulation of the granulation liquid is as follows: atomization pressure 0.1~0.5 MPa; spray rate 1~5 rpm; inlet air temperature 50~70℃; material temperature 35~50℃; backflushing temperature 35~50℃; fan speed 800~1500 rpm; air volume 30~80 m³ / h. 3 / h.

8. A highly thixotropic and easily dispersible hydroxyethyl cellulose ether particle for toothpaste, characterized in that, It is prepared by the method described in any one of claims 1 to 7.

9. Use of the highly thixotropic and easily dispersible hydroxyethyl cellulose ether particles for toothpaste according to claim 8 in the preparation of a thickener for toothpaste or in the preparation of toothpaste.

10. A toothpaste, characterized in that, Includes the highly thixotropic and easily dispersible hydroxyethyl cellulose ether particles for toothpaste as described in claim 8.

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