How does HPMC adjust the consistency and extrusiveness of toothpaste production, and does it affect the taste? ​

In toothpaste production,Hydroxypropyl methylcellulose (HPMC)As a commonly used adhesive, thickener, and stabilizer, its mechanism for regulating viscosity and extrusion properties, as well as its impact on taste, are as follows:

1、 The regulatory effect of HPMC on the consistency and extrusion properties of toothpaste

Consistency regulation mechanism

HPMC is a water-soluble polymer that forms a viscous colloidal solution when dissolved in water. The regulation of toothpaste consistency is mainly achieved through the following methods:

Concentration control: As the dosage of HPMC increases, the intermolecular interactions are enhanced, the viscosity of the colloidal system increases, and the consistency of the toothpaste is increased (thicker); On the contrary, a decrease in dosage leads to a decrease in viscosity (thinner).

Molecular weight influence: HPMC with high viscosity models (such as 100000 mPa · s or more) have longer molecular chains and form a denser colloidal network at the same concentration, which can significantly improve viscosity; Low viscosity models (such as those below 50000 mPa · s) have a weaker effect on improving viscosity.

Synergy with other ingredients: HPMC can interact with moisturizing agents (such as glycerol) and abrasives (such as calcium carbonate) in toothpaste, further adjusting the viscosity of the system by adsorbing, encapsulating particles, or binding with water molecules, avoiding delamination or precipitation.

Squeezing regulatory mechanism

The extrusion requirement for toothpaste is "easy to extrude but not flowing",HPMCBy improving the thixotropy (shear thinning characteristic) of the system, this balance is achieved:

When standing still, the colloidal network structure formed by HPMC molecules is stable, and the toothpaste maintains a high viscosity to avoid leakage from the tube mouth;

When squeezed (subjected to shear force), the molecular chains are stretched and arranged, the network structure is temporarily disrupted, the viscosity decreases, making it easier for toothpaste to be squeezed out of the tube mouth;

After extrusion, the shear force disappears, and the molecular chains re entangle to form a network. The toothpaste quickly recovers its consistency and maintains its shape (such as being in a strip shape that is not easily collapsed).

In addition, HPMC can improve the plasticity of toothpaste, reduce the phenomenon of "breakage" or "clumping" during extrusion, and make the extrusion process smoother.

2、 The Effect of HPMC on Toothpaste Taste

HPMC has a relatively small impact on taste, but there are still indirect effects:

Positive impact:

As a water-soluble polymer, HPMC can quickly mix with saliva in the oral cavity, increasing the lubrication of toothpaste and reducing the "roughness" caused by abrasive hardness;

Its stable colloidal structure can help other ingredients (such as essence and sweetener) disperse evenly, making the taste more harmonious.

Potential negative impacts:

If the dosage of HPMC is too high or the model selection is inappropriate (such as excessive use of high viscosity models), it may result in a slight "gelatinous" or "sticky" feeling of toothpaste remaining in the mouth, especially when rinsing mouth, which may feel difficult to rinse thoroughly; But under reasonable dosage (usually 0.5%~2%), this effect can be ignored.

summary

HPMCAdjusting the consistency of toothpaste through concentration, molecular weight, and synergistic effects, and improving extrusion through thixotropy, are key components in balancing the physical properties of toothpaste; Its impact on taste is slight, mainly reflected in enhancing lubrication, and it will not cause obvious discomfort when used reasonably. In production, the appropriate model and dosage of HPMC should be selected based on the texture requirements of the toothpaste, such as the softness and hardness of the paste and the smoothness of extrusion.