JPH0627633Y2 - Mixed granular super absorbent polymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a mixture of a granular superabsorbent polymer and rustproofed metal particles.

PRIOR ART Today, the most frequently used application of granular superabsorbent polymers is for disposable diapers. Briefly explaining the manufacturing process of these paper diapers, first, short pulp fibers are continuously dropped on a running long-sized tissue paper to form a belt-shaped fluff, and a granular superabsorbent polymer is continuously added thereto. Long, and relatively thick (about 20%) with a granular superabsorbent polymer incorporated.
mm) fluff FP. This plan view is shown in FIG. In order to apply this to individual disposable diapers as well, it is cut into a certain length (Fig. 7) to make a fluff water absorption zone or pad P containing a so-called granular superabsorbent polymer, and these are treated in the next step. It is sent by feeding one sheet at a time to a long plastic film, tissue paper, non-woven fabric, etc., sandwiching it, that is, sandwiching and adhering (Fig. 8), and finally, cutting the middle part of that time interval. (Fig. 9) to make individual disposable diapers.

[Problems to be Solved] There is one problem in the above-described conventional method for manufacturing a disposable diaper. That is, in the water absorbent zone, that is, the pad P shown in FIG. 7, the granular superabsorbent polymer was sprinkled and incorporated over the entire length of the pad. However, as shown in the phantom line in FIG. 9, the actual water-absorbing part may be only a small part of the “A” part in the central part, and the required amount of the granular superabsorbent polymer is also within that range. The dispersed state is the most suitable. However, if you apply a small pad in that range, that is, only the "A" part, it will not fit in the crotch of the baby and it will give you a feeling of strangeness. An appropriate size (), that is, a large pad P of the related art in which the granular superabsorbent polymer is incorporated over the entire length has been used. In essence, more polymer than was needed was wasted.

Therefore, as described above, it is desirable to incorporate the granular superabsorbent polymer only in a necessary small portion, that is, the "A" portion on the conventional pad P having an appropriate size, and various industry companies have been trying to improve it. It was An example of this is a small portion that requires a granular superabsorbent polymer on a long fluff. "
It was to sprinkle intermittently with the length of part "A".
In that case, the granular superabsorbent polymer is sprinkled or present (one end of the "A" portion) at a position of a required inward distance ₂ from the end portion of the pad P which is a standard length (on FIG. 9). There must be. To put it the other way around, it is the place ("
It suffices to detect the position of one end (t) of the "A" part and cut a part of the required fixed distance ₃ or determine the sprinkling position (t) with reference to the cutting position. However, the granular superabsorbent polymer etc. scattered in the thick fluff (about 20 mm) are bulky (about 70 mm).
Compared to the relatively large fluff (0 cc), it is extremely small (about 6 g), so that the increase in the fluff thickness due to the superabsorbent polymer is hard to be caught from the outside. Nor can the granular superabsorbent polymer be detected electrically or magnetically.

For the above reasons, the intermittent spraying of the granular superabsorbent polymer onto the fluff has not been put to practical use.

[Means for Solving the Problems] An object of the present invention is to provide a granular superabsorbent polymer capable of externally electrically or magnetically detecting the location of the granular superabsorbent polymer. .

That is, the conventional granular superabsorbent polymer is a mixed superabsorbent polymer in which metal particles are mixed in a required amount. At the same time, in order to prevent the metal particles from rusting and impairing the appearance, it is necessary to use those metal particles that have been subjected to a rust preventive treatment.

The gist of the present invention is a mixture of a granular superabsorbent polymer Pg and rustproof metal particles Mr.

The reason why the metal particles are mixed in the first place is to detect the existence position of the mixture by the metal detector. Consider the size of the metal particles in that case. According to an easily available metal detector which is generally available on the market, the detection ability thereof is a minimum iron particle size of 0.75 mmφ. Calculating based on this, if one weight of W = 1.735 mg with an iron particle size of 0.75 mm is dispersed on 100 mm ^{2 at an} equal interval, each iron particle interval becomes about 10 mm. ...... Also, if 4 pieces are dispersed on 100 mm ^{2 at} equal intervals, the distance between each iron particle becomes about 5 mm. …… In addition, the area where the granular superabsorbent polymer is built in, that is, the area where the polymer is spread (“A” part in FIG. 9) is spread to an area of 100 mm × 350 mm = 35,000 mm ² ……. The number of iron grains and their weight are: 35,000 × 1/100 × 1 = 350 in case of, and the weight is 1.735 × 350 = 0.6g in case of, 35,000 in the case of × 1/100 × 4 = 1,400 pieces ...
In the case of ..., the weight is 1.735 × 1,400 = 2.4 g ...
As described above, the dispersion interval is determined by the number of dispersed iron particles, which determines the accuracy of the location of the mixed granular superabsorbent polymer to be detected.

On the other hand, since the amount of the granular superabsorbent polymer applied to the above-mentioned area "A" part (about 35,000 mm ² ) is about 6 g, the weight ratio with these iron particles is 6: 0.6-2.
4, about 1: 0.1-0.4.

However, the above ratio is an example when a general metal detector is used, and it is said that when a metal detector with higher sensitivity is used, the above-mentioned several times higher sensitivity can be obtained. The smaller diameter, that is, the smaller weight can be detected. If the magnification of high sensitivity is 3 times, the mixing ratio of the above-mentioned mixed type granular superabsorbent polymer and iron particles is 1: 0.03 to 0.4.

Although the above-mentioned metal detector is of the magnetic type, it may be of the X-ray type.

It is desirable that the metal particles be processed for rust prevention. The reason is to prevent deterioration of the aesthetic appearance due to rusting.
As the anticorrosive treatment, chemical treatment is performed according to the type of each metal to form a film on the surface. However, it is advantageous to coat the plastic with respect to iron particles which are presumed to be commonly used. In the method, as shown in FIG. 5, iron particles Mp are air-sprayed in a chamber 1 by an air ejector 2, and liquid plastic P is air-sprayed and spray-coated. In this way, the surface of the iron particles is covered with the plastic film, that is, the rust-prevented iron particles Mr are obtained.

The reason why iron is most suitable as the material of the metal particles is that the cost is low and a relatively inexpensive magnetic detector can be used because it is a magnetic material. The magnetic substance is generally called, and refers to an iron-based alloy containing iron as a main component, such as nickel, cobalt, chromium, silicon, aluminum, and magnesium.

Further, granular super absorbent polymer Pg (particle size 100 to 350
μφ is granular Pk (length 150 to 3) depending on the manufacturing method.
00 μ) or crushed Pc (50 to 200 mesh) (including the flakes, which are also flakes, which is the shape of the polyethylene raw material obtained by polymerization in the production of medium-pressure polyethylene. ), Powdered Pp
(Particle size 10 to 80 μφ), which can be used,
In the powder form, the mixed iron particles or iron powder may settle during movement.

In the above case, the iron particles may be aluminum particles. In this case, an X-ray type metal detector is used. Aluminum particles may be used, but the foil pieces are more effective. That is, the aluminum foil pieces are mixed in a granular or granular, fragment-like, flake-like, or powder-like superabsorbent polymer.

In the above description, the description has been made for a disposable diaper, but the mixed superabsorbent polymer of the present invention can be applied to a sanitary napkin having the same structure.

[Advantages of the Invention] By incorporating the mixed type granular superabsorbent polymer according to the present invention into a necessary portion of the water absorbent zone in the paper diaper, it is possible to detect the position of the polymer in the manufacturing process of the paper diaper. It is possible to cut a predetermined part from the position. That is, it is possible to manufacture a disposable diaper in which the granular superabsorbent polymer is incorporated in the correct position. This can prevent the occurrence of defective products containing the granular superabsorbent polymer sprinkled at inaccurate positions, which has been frequently generated in the past, that is, it can contribute to the improvement of production efficiency and cost reduction. is there.

[Brief description of drawings]

Fig. 1 is an enlarged explanatory view of a mixed state of the granular superabsorbent polymer of the present invention and rustproofed metal particles. Fig. 2 shows a granular superabsorbent polymer and rustproofed metal particles. Expanded explanatory view of mixed state FIG. 3 is an enlarged explanatory view of mixed state of the fragment-shaped superabsorbent polymer and the metal particles subjected to rust-prevention treatment. FIG. 5 is an enlarged explanatory view of a mixed state with metal particles. FIG. 5 is an explanatory view of a method of coating the iron particle surface with plastic. FIG. 7 is a plan view of a pad obtained by cutting the band-shaped fluff into a certain length. FIG. 8 is a pad of each of the above-mentioned pads, which is sandwiched between a long plastic film and a non-woven fabric at a certain interval. Fig. 9 is a plan view of the thing. Plan view of individual disposable diapers cut to a certain length Explanation of main symbols 2 …… Metal particle ejection nozzle, 3 …… Liquid plastic spray nozzle, “A” …… Necessity of granular super absorbent polymer Range, FP ... Band-shaped fluff that is continuously sprinkled with granular superabsorbent polymer and built-in .... Required pad length, ₁ ... Length of "A" above, ₂ ... Pad Distance from end to end of "A" section, ₃ ... Distance from end of diaper to end of "A" section, t ...
... End of "A" section above

Claims (8)

[Scope of utility model registration request] 1. In a large number of particles of granular superabsorbent polymer,
A mixed-type granular superabsorbent polymer, characterized in that a smaller number of rustproofed metal particles are mechanically dispersed and mixed. 2. The mixed type granular superabsorbent polymer according to claim 1, wherein the rustproofing treatment is a coating of plastic on the surface of metal particles. 3. The mixed type granular superabsorbent polymer according to claim 1, wherein the metal particles are iron particles or other magnetic particles. 4. The mixed granular superabsorbent polymer according to claim 1, wherein the metal particles are metal foil pieces. 5. The mixed type granular superabsorbent polymer according to claim 1, wherein the granular superabsorbent polymer is a granular superabsorbent polymer. 6. The mixed granular superabsorbent polymer according to claim 1, wherein the granular superabsorbent polymer is a fragment-shaped superabsorbent polymer. 7. The mixed granular superabsorbent polymer according to claim 1, wherein the granular superabsorbent polymer is a powdered superabsorbent polymer. 8. The mixed type granular superabsorbent polymer according to claim 1, wherein the mixing weight ratio of the superabsorbent polymer of various shapes and the metal particles is 1: 0.03 to 0.4. .