JPS6149287B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to dentifrice compositions, particularly dentifrice compositions containing an abrasive whose abrasive properties have been reduced by the addition of certain particulate materials. A fundamental requirement of an effective dentifrice composition is that it must clean teeth by reducing or eliminating food debris, acquired films, plaque, and tartar deposits. A satisfactory dentifrice therefore always contains an abrasive. The dentifrice composition must remove these deposits without abrading the underlying tooth structure, ie, enamel and dentin. In addition to hardness, the abrasiveness of a detergent is governed by physical properties such as particle size, shape, strength, and brittleness. Dentifrice abrasives are selected to combine these properties to produce the necessary abrasion for tooth cleaning with as little abrasion as possible to the tooth surfaces. Price is a second important factor when choosing a toothpaste abrasive. Therefore, it is not possible to modify the physical properties of the abrasive too much, as this would result in a dentifrice composition that would be too expensive to be of practical use. For example, calcium carbonate, a commonly used abrasive, is readily available and cheap, making it an abrasive base material suitable for widespread use in toothpastes. Calcium carbonate is available in various grades differing in crystal form, particle size, surface area and density. Its abrasiveness and cleaning properties can be modified by formulating different grades or mixing with other abrasive materials such as phosphates, but generally This modification of cheap materials makes the product very expensive. The present invention shows that the addition of a surprisingly small amount of a water-insoluble particulate organic polymer with low abrasive properties and low average density to coarse-grained calcium carbonate can significantly reduce the abrasiveness of the calcium carbonate. It is based on what we have shown is possible. The addition of such small amounts of polymer has the added benefit of reducing the depth of scratches created in the tooth enamel and thus improving the effectiveness of calcium carbonate brushing on the teeth. According to the invention, therefore, granular calcium carbonate 75
~99.9% by weight, (a) less abrasive than calcium carbonate, (b) lower average density than calcium carbonate,
(c) and a dentifrice composition comprising a detergent comprising 0.1 to 25% by weight of a water-insoluble particulate polymeric material having a weight-based median diameter of 0.01 to 100 microns. The polymer suitable for the dentifrice composition of the present invention is the Talysurf method (British Dental
Journal, 133, No. 2.60-66, July 1922), its polishing degree is relatively lower than that of calcium carbonate. Furthermore, it is preferred that the polymer has a Moh's hardness of 3 or less. Suitable polymeric materials are thermoplastic resins, ie resins that can be melted and resolidified without losing their original properties. Although the relatively low hardness and stiffness properties of this type of resin alone would not make it effective for use as a detergent in dentifrice compositions, they are ideal for the purposes of the present invention. Suitable thermoplastic resins include acrylic resins such as polymethyl methacrylate and polyisobutyl methacrylate, cellulosic polymers such as cellulose acetate and cellulose acetate, polyamides, polyethylene, polypropylene, polystyrene, polyvinyl chloride and vinyl chloride and vinyl alcohol. It is a vinyl resin such as a copolymer with Preferred materials are polymethyl methacrylate and polystyrene. Such polymers are present in granular form in dentifrice compositions. That is, the polymer does not dissolve in the body of the toothpaste and exists as separate particles without substantially agglomerating. The particles may be solid, arranged in a grid, or hollow. Hollow or porous particles are particularly preferred since such a structure provides a lower density than the material. Particles of polymeric material should have a weight-based median diameter of 0.01 to 100 microns. The weight median diameter (WMD) is the particle diameter at which 50% by weight occurs. Keeping the WMD below 100 microns ensures that the particles do not impart a significantly gritty texture to the dentifrice composition. The preferred WMD of the particles is 0.01-50 microns. The particle shape of the polymeric material is not an essential condition to reduce the abrasiveness of calcium carbonate. Therefore, both spherical polymeric material particles and irregularly shaped particles are equally effective in this respect. The present invention is particularly effective against relatively coarse and inexpensive calcium carbonate, which has outstanding cleaning power and is less abrasive to tooth enamel. Additional advantages are obtained by incorporating the polymeric material into a calcium carbonate-based dentifrice composition that contains fluoride as a fluorophosphate or fluoride ion. It is well known that fluorophosphates or fluorides reduce effective fluoride ion activity because they form complexes with calcium carbonate. Experimental data conducted by the applicant shows that when using calcium carbonate as an abrasive in a fluoride-containing dentifrice composition and particles of less than 25% polymeric material,
This shows that the fluoride ion activity is improved compared to similar dentifrice compositions containing only calcium carbonate as an abrasive. For the purpose of illustrating the invention, FIG. 1 of the accompanying drawings shows
1 is a graphical representation of the results of measurements of the abrasiveness of toothpaste compositions containing various proportions of waterworks chalk with a WMD of 15 microns. The vertical axis in Figure 1 is the degree of abrasiveness of the mixture measured on a scale with 100% of the abrasiveness of the detergent present in the toothpaste sold in the UK under the trade name Macleans Freshmint. shows. The horizontal axis of FIG. 1 shows the weight percent of waterworks chalk in the mixture. Curve A shows the change in abrasion for a weight based mixture of elutriated chalk and precipitated calcium carbonate with a WMD of 4 microns. W used in this test.
Calcium carbonate with an MD of 4 microns is commercially available from Sturge Ltd. under the trade name Sturcal F, and is 2.7
It has a density of g/cc. From curve A, it can be seen that when the elutriated chalk during cleaning is replaced with Starcal F, the degree of polishing gradually decreases. 100 on this scale
The weight ratio of Starcal F to elutriated chalk must be 50:50 in order to produce a mixture with a polishing degree of . Curve B shows the variation in polishing degree for a weight-based mixture of elutriated chalk and polymethyl methacrylate, one of the polymers used according to the invention. The polymer was supplied by ICI as a DV400 grade powder with a WMD of 40 microns and a density of 1.1 g/cc. The abrasiveness of the mixture of elutriated chalk and methacrylate resin was tested on six toothpaste samples by the Talysurf method, and the results are shown in Table 1.

[Table] Figure 1 shows that when the elutriated chalk is replaced with a small amount of polymethyl methacrylate with a WMD of 40 microns, the degree of polishing is significantly reduced. A polishing degree of 100 is therefore obtained with a mixture of 90% elutriated chalk and only 10% methacrylate resin. The reason for this remarkable effect is illustrated by curve C. Curve C shows the polishing degree for a mixture of elutriated chalk and methacrylate resin, the mixing ratio of which is expressed on a volumetric basis. Curve C shows that replacing a certain volume of chalk with an equivalent volume of polymer results in a linear decrease in polishing. From this result, in order to obtain a type B curve in which the degree of polishing sharply decreases in a range close to 100% chalk for a small weight ratio of the polymer, the polymer must be (a)
It must have a low degree of abrasion such that the degree of abrasion at point Y of 100% polymer is much lower than the degree of abrasion at point X of 100% chalk, and (b) a small amount of weight of polymer in the mixture. % should be less dense than chalk so that it has a large volume %. In separate experiments, elutriated chalk and other polymers according to the invention, namely Pontybond (Pontyclun) were tested.
The polishing degree of a mixture containing a polymer commercially available under the trade name (manufactured by Chemical Co. Ltd.) was compared. Punchy bond of material used in this test
2150 has a WMD of approximately 15 microns. The particles are colorless, homogeneous spheres that are chemically inert but capable of absorbing small amounts of aliphatic liquids and relatively large amounts of aromatic liquids. The true density of Ponchy Bond is 1.005. The results of the polishing tests are shown in Table 2 and graphically shown in FIG.

[Table] These results show that by blending Pontey Bond with a WMD of 15 microns into elutriated chalk, the degree of polishing can be significantly reduced in this case as well. The method of reducing the abrasiveness of a detergent in a dentifrice composition by the method described herein is such that the polymer occupies a large portion of the effective volume of the dentifrice composition relative to its weight, thereby reducing the abrasiveness. Certain chalk particles can be used, which appear to interfere with the action of highly abrasive particles, which become proportionally less abrasive per unit volume when the abrasive is replaced by a polymer. It is not only the dilution effect caused by this. This is reflected in curve D of Figure 1, which shows the change in abrasiveness of a dentifrice composition caused by simply reducing the amount of dentifrice or elutriated chalk so that the weight of abrasive per unit volume becomes smaller and smaller. It is indicated by In this case no other abrasives or polymers were added to replace the chalk.
It can be seen that in this case the degree of polishing is reduced very gradually until most of the chalk has disappeared. A similar effect is seen when chalk is replaced by a corresponding weight of water. Experiments showing that the cleaning agent of the present invention has a low abrasiveness but an excellent polishing effect will be shown below in comparison with the case of using calcium carbonate alone. Comparative Experimental Example A toothpaste sample was used to polish the dentin of a human tooth set in a resin block. The block was fitted into a brush machine (BS5136:1981) and the exposed dentin was covered with PVC so that it became a 2mm wide band.
It was covered with tape. A slurry of the toothpaste sample was made and placed in a brush container. This sample 1A and sample 1B
The composition was as follows. Each block is 2000
The polishing degree and polishing effect were measured by brushing twice using a surface profilometer (Talysurf10). The composition of samples 1A and 1B was 4 parts by weight of detergent and 11
The cleaning agent for sample 1A is based on the carrier fluid in parts by weight.
100% elutriated chalk, sample 1B detergent is 80.1
Made from 19.9% elutriated chalk and 19.9% DV400 polymethyl methacrylate granules (ICI) (VMD40 micron). The carrier fluid conforms to the British Bureau of Standards (BSI) method BSI5136.
It was prepared by removing the detergent and adding water from the product described in , and had the following composition. %W/W Glycerin 40.32 Sodium carboxymethyl cellulose 2.26 Sodium saccharin 0.24 Sodium silicate 0.81 Sodium dodecyl sulfate 1.61 Formalin 0.16 Flavoring agent 1.29 Water Total 100 remaining The results of the test were as follows. (a) Polishing degree: Determined by measuring the average depth of the polishing grooves shown in Figure 3 (Sample 1A) and Figure 4 (Sample 1B). Average depth of sample polishing groove (μm) 1A 18 1B 5 Therefore, the polishing degree of sample 1B is slightly smaller than that of sample 1A.
It was 28%. (b) Polishing effect: The scratch depth, ie, the surface smoothness, shown in FIGS. 3 and 4 was measured. Sample average scratch depth (μm) 1A 1.7 1B 1.2 Therefore, the polishing effect of sample 1B was superior to that of sample 1A. The dentifrice compositions of the present invention may be in any form, such as a toothpaste, liquid, gel, ointment, emulsion, powder, tablet, dragee or chewing gum, and may be supplemented with the auxiliary ingredients normally included in such formulations. can include. Thus, for example, toothpastes usually contain, in addition to the abrasive agent as a cleaning agent, surfactants, wetting agents, binders, flavorings, preservatives and coloring agents, and in some cases tin fluoride, fluoride, etc. Fluorides such as ammonium or sodium monofluorophosphate may be included. Commonly used surfactants for toothpaste include sodium lauryl sulfate and N sulfoxylate.
- Sodium lauroyl, ricinoleic acid derivatives and sulforicinoleic acid derivatives. Suitable humectants include glycerin, sorbitol and other polyalcohols such as pentanediol and/or butanediol. To prevent component separation during storage, toothpastes require binders, such as gum tragacanth,
Sodium carrageenan, cellulose derivatives such as carboxymethylcellulose and cellulose ethers, polyacrylic acid and polyvinylpyrrolidone are used. The dentifrice composition also contains peppermint oil, spearmint oil,
It may contain the usual flavoring agents such as menthol, sagebrush oil, sycamore oil, eucalyptus oil, aniseed oil, rose oil and lavender oil and sweeteners such as saccharin and enin sodium. Preservatives that can be included in dentifrice compositions include, for example, p-hydroxybenzoic acid esters, hexachlorophene, and known surfactants. If desired, the dentifrice compositions may be colored using dyes or may include bleaching or brightening agents such as sodium perborate, magnesium peroxide, hydrogen peroxide-urea compounds. Examples of formulations for toothpastes containing abrasives according to the invention are shown in the following examples. Example 1 %W/W glycerin 30.00 Sodium carboxymethyl cellulose 1.1 Sodium saccharin 0.4 Calcium carbonate (WMD 10-15 microns) 45.0 Polymethyl methacrylate grains DV400 (WMD 40 microns) 5.0 Sodium lauryl sulfate 1.5 Flavoring agent Add an appropriate amount of water to 100.00 %W/W. Example 2 %W/W Glycerin 30.00 Sodium carboxymethylcellulose 0.95 Calcium carbonate (WMD 10-15 microns) 35.00 Polymethyl methacrylate grains DV400 (WMD 40 microns) 15.00 Sodium lauryl sulfate 1.5 Flavoring agent Appropriate amount Satucharin sodium Appropriate amount Add water to the above to 100.00 %W/W. Embodiments of the invention are summarized as follows. (1) The dentifrice composition according to the claims, wherein the particulate polymeric material is polymethyl methacrylate or polystyrene. (2) The dentifrice composition according to claim 1 or item 1 above, wherein the particulate polymer has a weight-based median diameter of 0.01 to 50 microns and a Moo hardness of 3 or less. (3) A dentifrice composition according to claim 1 or 2, wherein the polymeric material is present in an amount of 0.1 to 15% by weight of the detergent. (4) The dentifrice composition according to any one of claims 1 to 3 above, wherein the polymeric material is in the form of particles that are hollow or have pores. (5) Claims containing an ionic fluoride or fluorophosphate compound or the first claim containing an ionic fluoride or fluorophosphate compound
The dentifrice composition according to any one of Items to 3. (6) The fifth above, wherein the ionic fluoride or fluorophosphate is selected from tin fluoride, ammonium fluoride, or sodium monofluorophosphate.
The dentifrice composition described in Section 1. (7) Powdered calcium carbonate is a water-insoluble granular polymer that (a) has less abrasiveness than calcium carbonate, (b) has a lower average density than calcium carbonate, and has a Mo hardness of 3 or less. , a method for reducing the abrasiveness of granular calcium carbonate, comprising mixing granular polymeric material having a weight-based median diameter of 0.01 to 50 microns in a proportion of 0.1 to 25% by weight.

[Brief explanation of the drawing]

FIGS. 1 and 2 are graphs showing the degree of polishing of toothpaste compositions prepared by mixing elutriated chalk with various materials in various proportions. Curve A in Figure 1 represents the case where precipitated calcium carbonate is mixed on a weight basis, curve B represents the case where polymethyl methacrylate is mixed on a weight basis, curve C represents the case where polymethyl methacrylate is mixed on a volume basis, and Curve D shows the case when reducing the amount of elutriated chalk from the toothpaste. The curve in Figure 2 shows the case where Ponteybond resin is mixed with elutriated chalk. FIGS. 3 and 4 are enlarged views showing the degree of roughness of the polished surface obtained as a result of tests conducted using Sample 1A and Sample 1B, respectively.

Claims (1)

[Claims] 1 Granular calcium carbonate 75-99.9% by weight, (a) less abrasive than calcium carbonate, (b) lower average density than calcium carbonate, and (c) insoluble in water with a weight-based median diameter of 0.01-100 microns. A dentifrice composition comprising a cleaning agent comprising 0.1 to 25% by weight of a particulate polymeric substance.