CA1128704A - Disposable product and process of manufacture thereof - Google Patents

Abstract

ABSTRACT
A disposable product and a process for manufactu?-ing the disposable product on a flexible conveyor. The disposable product has an absorbent core formed by sand-wiching a corrugated tissue between two separate feeds of fluffed pulp. Upper and lower layers of wadding are pro-vided, the lower wadding being first folded around the absorbent core longitudinally and then an upper wadding is laid on top. The upper and lower waddings are then roller crimped together and die cut and shaped and turned ninety degrees. Thereafter, a water impervious sheet of material, such as polyethylene, is provided with a glue line on its edges and is fed across the top wadding and wrapped about the top wadding, the core and partially overlying the lower wadding. A sheet of non-woven material is then wrapped about the assembly and provided with a longitudinal strip or strips of pressue sensitive adhesive. A release paper is applied over the adhesive to protect it prior to use.
The lower layer of fluffed pulp is provided with recesses partially therethrough for accommodating subst?ntial dis-charges of material at a rate faster than absorption is possible so as to prevent leakage. These recesses are formed by embossing so that the material beneath the recesses are substantially compressed.

Description

137(~

rrhe sub]ect matter disclosed in this application is related to the subject matter disclosed in the applicant's copending applications 323~990, filed March 22, 1919 and 324,065, filed March 23, 1979.

ACKGROUND OF T~IE INVENTION

FIELD OF THE INVENTION
This invention relates to a disposable product, such as a diaper, or a sanitary napkin, and a process of manufacturing the same.

THE STATE OF THE PRIOR ART
Numerous patents exist on diapers and sanitary napkins and like disposable products provided with absorbent pads.
There has been much activity in the field of developing absorbent cores. In the past, the cores have either been sufficiently absorbent to accept a substantial quantity of discharge or did not have the ability to accommodate fluid flooding and thereby prevent leaking because the core did not have provision for rapid reception of the ~uantities of fluid when discharged at a rapid rate. Alternatively, cores of prior diapers and sanitary napkins that were capable of preventing leakage when receiving gushes of fluid were unable to absorb sufficient total quantities of fluid over a practical period of time because the means for accommodating flooding reduced total fluid capacity.
Various means were used for absorption and transfer and distribution of fluid in a core such as the longitudinally corrugated paper in the middle of the core as shown in ~nited States Patent No. 2,896,627. Recesses and wells have been formed in the cores such as are shown in United States Patent Nos.

-2-~ ~87~3~

3,593,717, 3,403,689, 3J046,~86J and 3,749,627. In llnited sta~e.s Patent No. 3,666,611 there is disclosed a pulp lay0r ha~ing a cen tral compressed portion. Embossing and folding has been used to enhance absorption quantities as disclosed in United States Patent No. 2,952,260. Sanitary pads and diapers have been made on flexible conveyors as is disclosed in United States Patent No. 3J291,131.
Other pertinent patents relating to the method of manufacturing absorbent pads on flexible con~eyors are United States Patents Nos.
2,973,760, 3,268,954, 2,872~023, 3,225,898~ 3,439,795, and 3,203,419.
The present invention overcomes the difficulties of the prior art by providing a process of manufacturing an absorbent pad for a diaper, sanitary napkin or like disposable product which simplifies ~he formation of the novel pad and which prevents loss of both total absorbability and accommodation of fluid flooding of the disposable product during the manufacture thereof thereby result-ing in a disposable product capable of withstanding gushes of fluid, yet which has an extremely high total absorbability.
Accordingly, a sanitary pad of the invention comprises an absorbent core having a corrugated tissue sandwiched between two layers of fluffed pulp, upper and lower layers of wadding above and below said absorbent core, a fluid impervious sheet wrapped about said upper wadding layer and said absorbent core and having edges bonded to said lower wadding layer, and a non-woven sheet material wrapp~r about said wadding, core and 1uid imper~ious sheet, said lower layer of fluffed pulp facing the wearer and being provided with embossed recesses therein, the material of said lower layer of fluffed pulp abo~e said recesses being highly compressed.

76;! ~

The process of the invention for manufacturing a sanitary pad comprises the steps o~ embossing a ~lrst ~lu~ed pulp layer to for~ recesses therein and compressed portions thereabov~ eeding said first fluffed pulp layer with said spaced recesses being in the lower face thereof on a lower wadding, feeding a corrugated sheet onto the upper face o~ said first layer, feeding a second fluffed pulp layer onto said corrugated sheet to form an absorbent core, lay-ing an upper wadding on said absorbent corel then roller crimping said upper and lower wadding together, die shaping and cutting the assembled material and turning same ninety degrees, then wrapping a fluid impervious sheet about said upper wadding and said absorbent core and bonding the spaced edges thereof to said lower wadding, and thereafter wrapping the assembly with non-woven sheet material.
In the preferred method, two separate layers of fluffed pulp are fed onto a ~lexible conveyor sandwiching a two-ply corrugated tissue sheet therebetween. Upper and lower t~o-ply wadding is disposed under and above the fluffed pulp layers. A sheet of polyethylene or like fluid-impervious material is wrapped about the upper flufed pulp layer and the upper wadding and extends so ~hat its edges overlie and are adhesively secured to the edge portions of the lower wadding.
The ends of ~he wadding are crimped and a sheet of non-woven material is wrapped about the assembly and secured by a pressure sensitive adhesive, which also serves as a means for securing ~he disposable product when in use. A release paper (e.g. silicone treated~ is applied over the adhesive to protect it before use.
It is therefore an object of the invention to provide a disposable product having spaced recesses therein~ The recesses are formed by embossing so that the material therebelow is highly compTessed. Embossing and thereby forming recesses having compressed 7~3~

portions therebelow is desi~able because the gushes of tYaste fluid are easily received and accom dated by the recesses but the com-pressed portions prevent fluid from gushing through the pad at the compressed locations therefore enhancing waste fluid distribution.
In the drawings, Figure 1 is a longitudinal section view of an embodim-ment of the invention in the form of a sanitary napkin;
Figure 2 is a plan vieti of the sanitary napkin with parts thereof being broken away;
Figure 3 is a ~ertical sectional view taken along the plane of line 3-3 in Figure l;
Figure 4 is a partial sectional view taken along the plane lJ of line 4-4 in Figure i~;
Figure 5 is a partial plan view of a modified form of lower layer;
Figure 6 is a partial plan view of another embodiment of the lower layer;
Figure 7 is a sectional detail view taken along the plane of line 7-7 in Figure 5; and Figure 8 is a sectional detail view taken along the plane of line 8-8 in Figure 6.
With continuing reference to the accompanying drawing, wherein like reference numerals designate similar parts through-out the various views, reference numeral 10 is used to generally designate a disposable product in the orm of a sanitary napkin ~LlZ8704 which lncludes ~n absorbent Gore 12,. This lnvention 1~ equally ~pplic,~le to a d~sposablc-! diaper or liXe product. The absorbent core 12 includ~s an upper layer 14 o~ ~lurfed pulp and a lo~er layer 16 of ~lu~fed pulp having recesses 18 ther~in which e~tcnd ~lmost, but not all the way, throu~h the fluffed pulp layer 16.
I`he recesses 18 are arranged to face the weRrer. The rece.sses 18 are about rour ~ifths the ~hickness o~ the lower layer 169 The reces~ses 18 are formed by hot or cold embossinæ ~hich serves to compres~s the material 19 underlying the recesses~ Grooves 21 may interconllect the recesses 18 sho~n in ~i~s, 5 and 7, mhese ~rooves may ~orm spac~d lines o~ recesses, ~he ~rooves 21 are -not as deep as the recesses 180 ~lter~at~ely linear grooves 23 as uell as tr~ns~rerse ~roo~res 25 and d~agonal groo~cs 27 and ~9 may i.nterconnect each recess with all ad~acent r~cesses. 'llhese groo~es may be as deep as the recesses and provide for optimum fluid Aistribution, A two-ply corrugated sheet of tl.ssue 20 is sandwlched bet~ie~n the flu~fed pulp layers 14 and 16 0 Belo~ the l~yer 1~ ls a two-ply wadding 22) whlle ~n upper t~o-ply ~add~ng 2~ o~erli~s the upper surface ~ the Mu~ed pulp layer 14~ ~ sheet of water impervlous ~aterlal 26, such as polyethylene, o~erlies the waddir 24 a~ extends about the core 12 and is secured to the ed~es of th~ lol!er wadding 22 by a~hesi~e or glue 28 provided on flange 7~4 port:ions 30 and 32. The flange por-tion~s do not ext~rld under the recesses 18, A sheek 34 o~ non~woven material, which overlies the lower wadding 2~, is wrapped to overlie the upper wadding ~l~ and the water impervious sheet 26 and may have its edges secured by pressure sensitive adhesive 36.
A strip 38 of silicone-release paper 38 is provided with pressure sensitive adhesive 40 and is secured to overlie the non-woven sheet 34. The ends of the wadding layers 24 and 22 and the ends oi~ the non-woven sheet 34 are roller crimped together as at 42. The recesses 18 and grooves 21 or 23 provide means :~or accommodating gushes of :fluid while the corrugated tissue 20, whlch is corrugated lengthwise3 provides for ~luid distribution from the absorbent pulp l~yer 16 to -the absorbent fluffed pulp layer lJ-~. The com-pressed areas 19 under the recesses and grooves prevent flood-ing of the corrugated tissue 20. The non-woven sheet 34 provides for a dry contacting surface~ while the water imperv-ious sheet 26 assures against leaking.
The sanitary napkln is manufactured on an endless belt conveyor using two separate sheets of fluffed pulp~
which are laid one over the other sandwiching the corrugated two-ply tissue 20 therebetween. The bottom layer of flu-ffed pulp is formed with recesses 18 thereinO The absorbent core is laid on the lower g ~7~ I

ra~ding 22, which s two;-ply, and which ls folded around the absorbent Gol~e longi.tud~nally w~ t:h the top waddin~ 24 being lQ~d on t;op and the top and b~ttom l~nddlngs are rolle~ cr~mped togeth~; O
Then, the st~lp assembly is die shaped and cut and then turned ninet~ degrees so that A sheet of polyethy~ene 26 ~ay be ~ed across the top and rolded around ~ bonded by lts ~lue lines to the lo~rer waddln~ 22, Thereafter, the napkin 1~ wrapped w.lth the non-woveIl sheet 34 and its ed~es secured by adhesl~e, ~hich Qlso se~ves to hold a silicone~release paper thereon ~or sealin~
purposes when the pad is not ln use.
Many ~odifications and ~ar1ations Or the s~nit~ry napl~in and the proc.ess o~ manufac~uri~g may be made ~ithln the li~ht of this disGlosure and it is to ~e understood that the ~nver _ tion may the.e~ore be practiced lqithin the scope o~ the appended cl~ .s,

Claims (9)

WHAT IS CLAIMED IS:

1. A sanitary pad comprising an absorbent core having a corrugated tissue sandwiched between two layers of fluffed pulp, upper and lower layers of wadding above and below said absorbent core, a fluid impervious sheet wrapped about said upper wadding layer and said absorbent core and having edges bonded to said lower wadding layer, and a non-woven sheet material wrapper about said wadding, core and fluid impervious sheet, said lower layer of fluffed pulp facing the wearer and being provided with em-bossed recesses therein, the material of said lower layer of fluffed pulp above said recesses being highly compressed.

2. A sanitary pad according to claim 1, including a silicone release strip adhesively secured to and overlying said non-woven sheet.

3. A sanitary pad according to claim 1, wherein said recesses extend about four fifths the thickness of said lower layer of fluffed pulp.

4. A sanitary pad according to claim 1, including grooves in said lower layer of fluffed pulp interconnecting said recesses.

5. A sanitary pad according to claim 4, wherein said grooves are as deep as said recesses.

6. A sanitary pad according to claim 4, wherein said grooves are shallower than said recesses.

7. A process of manufacturing a sanitary pad comprising the steps of embossing a first fluffed pulp layer to form recesses therein and com-pressed portions thereabove, feeding said first fluffed pulp layer with said spaced recesses being in the lower face thereof on a lower wadding, feeding a corrugated sheet onto the upper face of said first layer, feeding a second fluffed pulp layer onto said corrugated sheet to form an absorbent core, lay-ing an upper wadding on said absorbent core, then roller crimping said upper and lower wadding together, die shaping and cutting the assembled material and turning same ninety degrees, then wrapping a fluid impervious sheet about said upper wadding and said absorbent core and bonding the spaced edges thereof to said lower wadding, and thereafter wrapping the assembly with non-woven sheet material.

8. A process according to claim 7, including the step of applying adhesive to the edges of said non-woven sheet material and then attaching a silicone-release paper in overlying relationship to said edges.

9. A process according to claim 8, wherein said non-woven sheet ma-terial is provided with pressure sensitive adhesive thereon.