MXPA01005669A - Absorbent articles - Google Patents

Abstract

The invention relates to an absorbent article that includes a synergistic combination of a) a pH-regulating substance in the form of a partially neutralised superabsorbent material, and b) lactic acid bacteria wherein after being wetted and worn close to the skin, the article has a pH value in the range of 3.5-5.5, preferably within the range of 3.5-4.9, and most preferably within the range of 4.1-4.7.

Description

ABSORBENT ITEMS FIELD OF THE INVENTION The present invention relates to absorbent articles of the kind used in contact with the user, such as diapers, incontinence guards, sanitary napkins and the like. The invention also relates to methods for reducing unwanted side effects that sometimes occur when these articles are used.

KNOWN TECHNIQUES Absorbent articles of this kind are known in many different forms, the absorbent body of such products normally being produced by dry defibrillation of the cellulose pulp, for example, cellulose pulp in the form of a roll, bale or sheet, , and converting defibrillated pulp dry, in a fluffy state to a pulp mat, sometimes with a mixture of so-called superabsorbents. The superabsorbents are polymers that can absorb several times their own weight of water or body fluid. A common problem related to absorbent articles such as diapers, sanitary napkins, incontinence guards or the like is that their use can give rise to unwanted side effects, such as skin irritation and odor. These problems can occur as a result of occlusion, the presence of moisture and factors of a mechanical, microbial and enzymatic nature, all of which coerce and amplify the effect of others to different degrees. For example, some unwanted side effects may occur as a result of or in conjunction with an increase in pH. US 3,794,034 discloses the importance of the pH in an absorbent article and also teaches the impregnation of the article with buffer substances by means of which the pH in the article can be maintained between 3.5-6.0, which is beneficial with respect to the inhibition of the growth of unwanted bacteria and with this the presence of undesirable odor, and also avoiding negative effects on the skin. EP 0,0311,344 describes the pH control in absorbent articles, wherein the buffering properties are obtained with the aid of a partially neutralized superabsorbent material and an antimicrobial substance chosen from among the nitrogen-based compounds or ordinary bis-guanide compounds . Unwanted side effects can be reduced by controlling the pH of the item, so that a certain level is not exceeded. However, not all harmful microorganisms are negatively influenced by a low pH value. Escherichia coli, which by itself is an acid producer, is an example of such a microorganism. Antimicrobial substances can also give rise to problems. For example, these substances give rise to allergies or irritation of the skin with prolonged use. In addition, it is in general discussion whether the extensive use of antibiotics may or may not give rise to an increase in antibiotic resistance by harmful bacterial strains. Finally, the use of antibiotics can have negative ecological consequences with respect to waste management. Attempts have also been made to solve the aforementioned problems of undesirable odors and the growth of undesirable microorganisms by actively adding the specific microorganisms to the absorbent articles of the aforementioned kind. For example, such a technique is described in WO 97/02846. These specific microorganisms are mainly lactic acid-producing bacteria, such as the different species of strains Lactobacillus and Lactococcus, which have an antagonistic effect with other microorganisms. However, the known techniques mentioned above have not completely eliminated the problems of undesirable odors and the growth of undesirable microorganisms. As a result, improvements are needed that can also reduce the problems associated with bad odor and the growth of microorganisms.

SUMMARY OF THE INVENTION It has now been surprisingly found that the aforementioned problems associated with undesirable side effects such as odor and skin irritation can be further reduced by using an absorbent article containing a synergistic combination of: a) a pH regulating substance in the form of a partially neutralized superabsorbent material, and b) lactic acid bacteria, where the pH value of the article after being moistened when used against the skin is in the range of 3.5-5.5, preferably within the range of 3.5-4.9, and more preferably within the range of 4.1-4.7.

DEFINITIONS The term "absorbent article" when used in this document refers to absorbent articles that are used against the skin, such as diapers, incontinence guards and sanitary napkins. The term "superabsorbent" and the acronym "SAP" refers to polymers that can absorb several times their own weight of water or body fluid. A suitable, partially neutralized superabsorbent material may be composed of crosslinked polyacrylate of the kind described in EP 0,392,108, although it is possible to use other types of superabsorbent material having corresponding properties. The term "lactic acid bacteria" and the abbreviation "LB" refers to a group of bacteria that produce lactic acid with normal fermentation. Examples of bacterial species that include strains belonging to this group are Lactobacillus, Lactococcus, Leuconostoc and Pediococcus. Bacteria of the Lactobacillus and Lactococcus families are preferred. The term "CTMP" refers to chemithermomechanical pulp. The term "CP" refers to cellulose chemical pulp.

The term cfu refers to colony forming units. The invention will now be described with reference to the accompanying drawings, in which: Figure 1 shows a diaper of the invention from the side proposed to make contact with the user during use; Figure 2 is a diagram illustrating the culture of Escherichia coli in an absorbent article containing: 1) CTMP + traditional superabsorbent; 2) CTMP + traditional superabsorbent + lactic acid bacteria; 3) CTMP + partially neutralized superabsorbent; and 4) CTMP + lactic acid bacteria + partially neutralized superabsorbent; and Figure 3 is a diagram illustrating the cultivation of Enterococcus faecalis in an absorbent article containing: 1) CTMP + traditional superabsorbent; 2) CTMP + traditional superabsorbent + lactic acid bacteria; 3) CTMP + partially neutralized superabsorbent; and 4) CTMP + lactic acid bacteria + partially neutralized superabsorbent.

DETAILED DESCRIPTION OF THE INVENTION An absorbent article in which the problem associated with undesirable side effects, such as skin irritation and unpleasant odors, is further reduced by combining in the article a pH regulating substance in the form of a partially superabsorbent material neutralized, with lactic acid bacteria. Swedish patent application 9702298-2 discloses an absorbent article which includes a pH regulating substance in the form of a partially neutralized superabsorbent material which, when moistened, produces a pH in the range of 3.0-4.9 in the absorbent article. It has been found that such a value has a growth inhibitory effect on unwanted microorganisms in the article. It also deteriorates the activity of certain enzymes that affect the skin, such as lipases and proteases. According to the invention, an absorbent body may also include absorbent material different from the partially neutralized superabsorbent material. The cellulose pulp is an example of such a material. It has been found beneficial to use a partially neutralized superabsorbent material according to the above in combination with cellulose having a pH below 7., and preferably below 6. A suitable cellulose pulp is chemithermomechanical pulp (CTMP) with a pH = 2.5-8.5, preferably 2.5-6.5 and more preferably 2.5-5.5. Another convenient pulp is chemical cellulose pulp having a pH = 2.5-8.5, preferably 2.5-8.0 and more preferably 2.5-7.0. The cellulose pulp can acquire a convenient acidity by controlling the pH of the pulp during the manufacturing process, for example, by adding an acidifier. This acidifier can, for example, be S02-water. Otherwise, it is possible to add a suitable acid to the finished pulp. As already mentioned, cross-linked superabsorbent polyacrylates suitable for use in the present invention are described in EP 0,391,108. It is also possible to use other superabsorbent materials having the same properties as those already mentioned. A suitable proportion of the superabsorbent material in the article is 5-100%, preferably 15-60% and most preferably 15-50%. SE 9702298-2 describes the relationship between the degree of neutralization and the pH of the aforementioned superabsorbent material. It is evident that the degree of neutralization will preferably be between 20% and 45%, and more preferably between 20% and 35%. The diaper 100 shown in Figure 1 includes a liquid-permeable molded sheet 1 made, for example, of non-woven material or perforated plastic film, a molded sheet impervious to liquids 2, made for example of plastic film or non-woven hydrophobic fabric, and an absorbent body 3 contained between the molded sheets 1,2. It is proposed that the diaper cover the lower part of the user's trunk in the form of underpants. Accordingly, the diaper includes two end portions 4, 5 and a narrower part for the crotch 6, between the end portions, the crotch portion being proposed to be placed between the wearer's legs in the crotch region when it is in place. In use. The diaper includes fastening tabs 7 near the back edge of the waist 8 of the diaper to allow the diaper to be secured in the desired pant configuration. During use, the securing tabs 7 are fastened to the front part 5 of the diaper, close to the front edge of the waist 9, to hold the diaper around the wearer's waist. The diaper shown in Figure 1 also includes pre-stretched elastic devices 10, which may consist of elastic tape, and elastics covered with cord, elastic foam or some other suitable material. For purposes of simplicity, the elastic devices 10 have been shown in an extended state in Figure 1. As soon as the tension in the elastic devices is released, the devices will make contact and thereby form the elastic holes for the legs in the diaper. . The absorbent body 3 of the diaper embodiment shown in Figure 1 is composed of two layers 11, 12, namely, an upper layer for collecting liquids 11 and a lower layer for storing liquids and dispersing liquids 12. The layer upper intake 11 must be able to receive large volumes of liquid for a short period of time, that is, it must have high capacity for liquid absorption instantaneously, while the lower liquid storage and dispersing layer 12 must have a high capacity of dispersion of liquids and must be able to brake liquids from the capture layer 11 and disperse this liquid to the storage and dispersion layer 12. The differences in the respective properties of the two layers 11 and 12 can be achieved by arranging the differences in density, with which a more densely compressed fiber structure will disperse the liquid more effectively compared to the fib structure corresponding lower density, which, as a result of its larger pore size, has a greater liquid absorption capacity instantaneously and a lower liquid dispersion capacity. The differences in the absorption capacity of the two layers can also be achieved with the help of different fiber structures that have mutually different properties. For example, the fluffy pulp of cellulose produced by chemical means has a greater liquid dispersion capacity in comparison, for example, the pulp that is produced by mechanical or chemimetromechanical means, called CTMP. A fiber structure containing chemically stiffened cellulose fibers will also have a higher liquid absorption capacity but lower liquid dispersion capacity compared to traditional chemical pulp. Natural fiber batt or fluffed nonwoven material are examples of other suitable materials for use in the catchment layer 11. A pH reducing substance in the form of a partially neutralized superabsorbent is mixed with the upper liquid capture layer 11 of the absorbent body 3. This part of the absorbent body 3 also includes lactic acid bacteria. A partially neutralized superabsorbent that functions as a pH regulating substance has a lower total absorption capacity and a lower absorption rate compared to traditional superabsorbents. An advantage with the placement of a superabsorbent like this in the upper part of the absorbent body closest to the user is that in this mode the caking of the swollen superabsorbent is reduced. A common problem is the so-called gel blockage caused by the agglutination of the swollen superabsorbent. Gel blocking means that when the superabsorbent is moistened it forms a gel that blocks the pores in the porous structure and thereby prevents the transport of liquid from the wetting region to other parts of the absorbent structure. A traditional superabsorbent is mixed in the lower layer for storage and dispersion of liquid 12 of the absorbent body 3. An advantage that is produced by placing the traditional superabsorbent in the lower layer for storage of liquids 12 is that the traditional superabsorbent has a greater absorption capacity total compared to a partially neutralized superabsorbent that has a pH regulating effect. It will be understood that the invention also includes other constructions of the absorbent body. The absorbent body may include the partially neutralized superabsorbent and traditional superabsorbent, both superabsorbents being evenly distributed in the upper layer and the lower layer of the absorbent body. In addition, it is possible to use only one type of superabsorbent material in addition to the cellulose pulp. In such cases, the superabsorbent material has the form of superabsorbent which will also function as a pH regulating substance. Layers other than the liquid capture layer 11 in the absorbent body 3 may also include lactic acid bacteria and it is also possible to include lactic acid bacteria in / on the molded sheet permeated to the liquids of the article. The invention will now be described with reference to the following example, which is provided for purposes of illustration only and which has no limiting effect of the invention.

Example Tests were performed using sterile synthetic urine which included a growth medium for microorganisms. The synthetic urine contained monoions, divalent ions, cations and anions and was prepared according to the information contained in Geigy, Scientific Tables, Vol. 2, 8th edition, 1981, p. 53. The microorganism growth medium was based on information related to Hoo and medium FSA for enterobacteria. The mixture had a pH of 6.6. The absorbent bodies were produced with the aid of a sample body former slightly modified according to SCAN C 33:80. The coated pulp and the superabsorbent material of a desired type were weighed and a uniform mixture of the fluffed pulp and the superabsorbent material was then passed in an air stream to a vacuum pressure of approximately 85 mbar through a tube with a diameter of 5 cm and provided with a metallic bottom net on which a thin tissue had been placed. The mixture of the fluff pulp and the superabsorbent material was collected on the fabric in the metal net and the absorbent body was formed. The absorbent body was then weighed and compressed to a relative density of 6-12 cm 3 / g. The absorbent bodies contained 0.85 g of CTMP and 0.15 g of superabsorbent material. Two different superabsorbents were used, these being the traditional superabsorbent with a pH of about 6 and partially neutralized superabsorbent with a pH of about 4.2. In the case of using lactic acid bacteria, these bacteria consisted of Lactobacillus plantarum, strain LB931, which had been deposited in Deutsche Sammlung von Mikroorganismen (Braunschweig, DE) and with a deposit number DSM 11918. The LB931 was dried by freezing in skimmed milk. The concentration of the i-bacteria was adjusted to 109-1010 ufe / gram, mixing the bacteria with skimmed milk powder. The absorbent bodies were prepared according to the above method. Synthetic urine was prepared according to the aforementioned. Escherichia coli (Ec) and Enterococcus faecalis (Ef) were grown in nutrient broth (Nutrient Broth Oxoid CM1) overnight at 30 ° C. The grafted cultures were diluted and the bacterial contents were calculated. The cultures were mixed in different proportions, so that the final culture mixture contained approximately 104 organisms per ml of synthetic urine. 10 ml of the synthetic urine were poured into a sterile sputum bottle of 70.5 x 52 mm, volume 100 ml and the absorbent body was placed on top placed down the bottle and allowed to absorb liquid for 5 minutes, after which the bottle was removed and incubated at 35 ° C for 0, 4, 8 and 12 hours, respectively, after which the bacterial count in the absorbent body was determined. TGE agar was used in the culture process to measure the total number of bacteria, and Drigalski agar and Slanetz Bartley agar were used for the specific measurement of Escherichia coli and Enterococcus faecalis, respectively. LB931 was measured on MRS agar (from Man Rogosa Sharpe). When strain LB931 was added to the absorbent body, it was added in an amount corresponding to 10 mg of the freeze-dried mixture, mixed with 10 ml of synthetic urine, which was then added immediately to the sample body. The results of these tests are listed in the following table: Bacterial growth in absorbent articles with or without partially neutralized superabsorbents and lactic acid bacteria, respectively.

I. E. Coli: Body type Oh 4h 8h 12h absorber log ufc / ml CTMP + SAP 3.7 5.3 9.2 9.4 CTMP + SAP + LB 3.8 5.3 9.0 9.4 CTMP + SAP acid 3.7 4.7 7.8 9.0 CTMP + SAP acid 3.5 4.5 5.6 5.7 + LB II. Enterococcus faecalis: Body type Oh 4h 8h 12h absorbent log ufe / ml \? w w CTMP + SAP 3.9 5.6 8.3 8.3 CTMP + SAP + LB 3.9 5.4 7.2 7.5 CTMP + SAP acid 3.9 4.7 6.1 7.4 CTMP + SAP acid 3.9 4.4 4.6 4.6 + LB III. LB931: Body type Oh 4h 8h 12h absorbent log ufc / ml \? \\ \? CTMP + SAP + LB 7.7 7.8 8.4 8.5 CTMP + SAP acid 7.5 7.9 8.5 8.7 The partially neutralized superabsorbent is designated "acid SAP" in the table above.

It will be apparent from the above table that the combination of partially neutralized superabsorbent and lactic acid bacteria have a synergistic effect with respect to the reduction in growth of Escherichia coli and Enterococcus faecalis. Division III in the above table also shows that LB931 grows equally well in the presence of partially neutralized superabsorbent as in the presence of traditional superabsorbent. These results are also shown in Figures 2 and 3.

Claims (10)

1. An absorbent article that includes a synergistic combination of: a) a pH regulating substance in the form of a partially neutralized superabsorbent material, and b) lactic acid bacteria, where the pH value of the article after being moistened and when used against the skin is in the range of 3.5-5.5, preferably in the range of 3.5-4.9, and more preferably in the range of 4.1- 4.7.

2. The absorbent article according to the claim 1, characterized in that the article includes at least one other absorbent material.

3. The absorbent article according to the claim 2, characterized in that the material includes chemithermomechanical cellulose pulp (CTMP).

4. The absorbent article according to claim 2, characterized in that the article includes chemical cellulose pulp (CP).

5. The absorbent article according to any of claims 1-4, characterized in that the lactic acid bacteria belong to the Lactobacillus family.

6. The absorbent article according to claim 5, characterized in that the lactic acid bacteria belong to the family Lactobacillus plantarum strain LB931, such strain having been deposited in Deutsche Sammlung von Microorganisemen (Braunsch eig, DE) and with the number DSM 11918.

The absorbent article according to any of claims 3-6, characterized in that the cellulose pulp contains an acidifier.

The absorbent article according to any of claims 2-7, characterized in that the article includes a wrapped absorbent body that includes an upper layer for capturing liquids (11) including partially neutralized superabsorbent material proposed to be close to the user during the use, and a lower layer for storage and dispersion of liquid (12) which includes traditional superabsorbent material and which is proposed to be distant from the user during use.

9. The absorbent article according to any of claims 1-8, characterized in that the number of lactic acid bacteria in the article is 104-101: Lfe.

10. The absorbent article according to claim 9, characterized in that the number of lactic acid bacteria in the article is 106-1 [sic].