Cleaning product

An 11.times.11 inches meltblown web contains a sufficient amount of condensed liquid detergent to wash a load of laundry and does not exhibit an objectionable sticky feel.

BACKGROUND OF THE INVENTION 
Laundry detergents are most commonly available in either liquid or powder 
form. In order to use such detergents, the user must measure out a certain 
quantity from a supply bottle or box and pour the measured amount into the 
clothes washer. In addition, if a fabric softener is desired, the fabric 
softener must be separately measured or at least separately deposited into 
the washer or dryer. Such multiple products, containers, and measuring can 
be messy and, at the very least an inconvenience, particularly for 
apartment dwellers who must carry all the necessary containers, etc., to 
the laundry area. 
In this regard, the prior art discloses a variety of alternative cleaning 
products which are intended to provide improved convenience to the 
consumer. For example, U.S. Pat. No. 4,356,099 to Davies et al. discloses 
a laundry cleaning product comprising a plastic bag containing a liquid 
detergent. The bag has a weak seal which is opened by the mechanical 
action of the washing machine, thereby releasing the liquid detergent. 
U.S. Pat. No. 4,188,304 to Clarke et al. discloses a similar detergent 
product comprising a plastic bag containing a particulate detergent. The 
bag contains a water-sensitive seal which discharges the contents of the 
bag when contacted with water. 
U.S. Pat. No. 3,686,075 to Morton discloses a sheet substrate containing a 
fabric softener which is to be preferably used in the clothes dryer, but 
can also be added to a wash machine during its rinse cycle. 
U.S. Pat. No. 4,170,565 to Flesher et al. discloses a laundry product 
comprising a detergent composition contained between two layers of a 
water-insoluble permeable substrate such as a polypropylene meltblown web. 
When contacted by water during the wash cycle, the detergent is dissolved 
and permeates through the substrate into the wash water. Most 
significantly, at column 1, lines 56-65, Flesher et al. apparently 
recognize the potential value of a single layer substrate for delivering 
laundry detergent, but conclude it is not feasible because of difficulty 
in loading the substrate with a sufficient amount of detergent and the 
sticky feel of any product that might be produced. 
Therefore there is a need for a laundry cleaning product containing a 
premeasured amount of detergent which is convenient to use and economical 
to manufacture. 
SUMMARY OF THE INVENTION 
In one aspect, the invention resides in a laundry cleaning product 
comprising a meltblown substrate containing at least 150 grams of 
condensed liquid detergent per square meter. Preferably, the amount of 
condensed liquid detergent is at least about 190 grams per square meter, 
which is the equivalent of 1/8 cup of liquid laundry detergent. A suitable 
range is from about 190 to about 300 grams per square meter. It has been 
discovered that meltblown webs possess a unique ability to absorb and hold 
an amount of liquid detergent sufficient to wash a load of laundry and, at 
the same time, do not exhibit a greasy or sticky feel which would be 
objectionable to users. In addition, the meltblown webs of this invention 
release the detergent over a sustained period of time, thereby improving 
washing efficiency. The product can be dispensed in sheet form or from 
perforated rolls. In addition, the single sheets can be perforated to be 
torn in half for half loads of laundry. 
The meltblown substrate can be any meltblown web made from a thermoplastic 
polymer having a softening point greater than 220.degree. F. Polymers 
which soften at lower temperatures may melt if exposed to clothes dryer 
temperatures. A preferred polymer is polypropylene, which is the most 
commonly used polymer for making meltblown webs. The process for making 
meltblown webs is well known in the art and is used extensively for 
manufacturing a wide variety of commercial nonwoven products. A 
representative example of the meltblowing process is disclosed in U.S. 
Pat. No. 3,978,185 to Buntin et al. dated Aug. 31, 1976. It will be 
appreciated, however, that other meltblowing process will produce webs 
suitable for purposes of this invention. The meltblown web can be combined 
or laminated to other supporting webs, such as spunbonded webs, in order 
to impart strength or other attributes to the product. 
The basis weight for a single sheet of the meltblown webs of this invention 
can range from about 80 to about 300 grams per square meter. Preferably 
the basis weight will be from about 110 to about 250, and most preferably 
about 180 grams per square meter. Basis weights lower than the abovesaid 
range lack sufficient pore volume to hold the necessary amount of liquid 
detergent. Basis weights greater than the abovesaid range are too 
difficult to manufacture. It is within the scope of this invention, 
however, to incorporate more than one ply into the product to increase the 
detergent load. 
The size of the meltblown web can be from about 200 to about 2000 square 
centimeters, preferably from about 600 to about 1,000 square centimeters, 
and most preferably about 800 square centimeters. The minimum size of the 
web is limited by the amount of liquid detergent the web can absorb and 
hold. The maximum size is determined by consumer acceptance, convenience 
and packaging considerations. 
The liquid detergents useful for making the products of this invention can 
be any liquid detergent which is suitable for cleaning laundry. As is well 
known in the detergent arts, these detergents typically contain a large 
number of components such as surfactants, solubilizers, pH adjusters, 
fragrances, brighteners, dyes, anti-redeposition compounds, and builders. 
For purposes of processing, as will be explained herein, it is preferable 
that the liquid detergent contain at least 60 weight percent active 
detergent solids in order to minimize drying costs, although liquid 
detergents having at least 25 weight percent solids are suitable. 
It is preferred that the meltblown web also contain a fabric softener which 
softens the laundry during the drying cycle. Webs impregnated with such 
softening agents are well known in the art and are well known commercial 
products. Suitable fabric softening agents include those described in U.S. 
Pat. No. 3,686,025 to Morton, dated Aug. 22, 1972.

DETAILED DESCRIPTION OF THE DRAWING 
Directing attention to FIG. 1, shown is a supply roll 1 of the meltblown 
web material to be saturated with liquid detergent. Preferably the web has 
been thermally pattern-bonded to provide sufficient integrity to withstand 
a wash and dry cycle without disintegrating. The web 2 is passed through a 
series of tension control rolls 3A, 3B, 3C, and 3D and fed to the 
saturation station 5. The saturation station consists of a tray 6 filled 
with liquid detergent 7 and a guide roll 8 which submerses the web. The 
space between the guide roll and the metering roll is set in order to 
control the amount of add-on to the web. The residence time of the web in 
the liquid detergent is short but sufficient to substantially saturate the 
web. Generally residence times on the order of one or two seconds are 
suitable. 
After leaving the saturation station, the saturated web 11 passes through a 
controlled nip between nip rolls 12 and 13 which serves to squeeze out 
excess liquid and provide an additional degree of control over the amount 
of liquid contained within the web and its even distribution throughout. 
The saturated web then passes through a dryer 15, preferably an air 
flotation dryer, which removes substantially all (about 95 percent) of the 
available moisture to condense the liquid detergent. The product leaving 
the dryer contains concentrated liquid detergent having a gel-like 
consistency, yet the web feels dry to the touch. 
After drying, the dried web passes around a tension control roll 16, a pull 
roll 17, a slitter roll 18, a Mount Hope roll 19, and a rewind drive roll 
20. The web is thereby wound onto the rewind roll 21 for subsequent 
converting and packaging operations. 
EXAMPLES 
Example 1 
A laundry cleaning product was made using the method described in 
connection with FIG. 1. A thermally pattern-bonded web of polypropylene 
meltblown material having a basis weight of 110 grams per square meter was 
passed through the dip tank at a speed of 17 feet per minute. The dip tank 
contained a liquid detergent solution of Watkins Concentrated Heavy Duty 
Liquid Detergent. The residence time of the web in the liquid detergent 
was 1.8 seconds. The active solids content of the detergent solution was 
63 weight percent. The gap between the guide roll and the metering roll 
was 0.030 inch. 
After the web exited the dip tank, the detergent-containing web was dried 
in an air flotation dryer to remove substantially all free water. The 
resulting web contained about 175 grams of condensed liquid detergent per 
square meter. The web was then wound onto a take-up roll. 
Product samples having a size of 11.times.14 inches were cut from the 
take-up roll and tested for washing efficacy. The products exhibited good 
washing efficacy and had only a slight oily feel. 
Example 2 
The method described in Example 1 was repeated using a polypropylene 
meltblown web having a basis weight of 140 grams per square meter. Because 
of the heavier basis weight, the gap between the guide roll and metering 
roll was increased to 0.040 inch. The solids add-on for the resulting 
product was 202 grams per square meter. Product samples were cut from the 
take-up roll to a size of 11.times.13 inches and exhibited good washing 
efficacy. 
Example 3 
The method described in Example 1 was repeated using a polypropylene 
meltblown web having a basis weight of 180 grams per square meter. The gap 
between the guide roll and metering roll was 0.050 inch. The solids add-on 
for the resulting product was 259 grams per square meter. Product samples 
were cut from the take-up roll to a size of 11.times.10 inches and 
exhibited good washing efficacy. 
It will be appreciated that the foregoing examples, shown for purposes of 
illustration, are not to be construed as limiting the scope of this 
invention.