U.S. patent application number 11/597961 was filed with the patent office on 2007-10-04 for sanitary thin paper and process for producing the same.
This patent application is currently assigned to Daio Paper Corporation. Invention is credited to Akira Hirasawa, Saeko Ito, Hiroshi Ono, Yoshinori Shimizu, Tetsuya Uehara.
Application Number | 20070233024 11/597961 |
Document ID | / |
Family ID | 35462944 |
Filed Date | 2007-10-04 |
United States Patent
Application |
20070233024 |
Kind Code |
A1 |
Uehara; Tetsuya ; et
al. |
October 4, 2007 |
Sanitary Thin Paper and Process for Producing the Same
Abstract
A sanitary thin paper is provided which has an excellent
pliability together with an excellent smoothness. Such a paper can
be obtained by incorporating a fatty acid ester-based compound and
a fatty acid amide-based compound internally and/or externally.
Inventors: |
Uehara; Tetsuya; (Shizuoka,
JP) ; Shimizu; Yoshinori; (Shizuoka, JP) ;
Ono; Hiroshi; (Shizuoka, JP) ; Hirasawa; Akira;
(Shizuoka, JP) ; Ito; Saeko; (Shizuoka,
JP) |
Correspondence
Address: |
KODA & ANDROLIA
2029 CENTURY PARK EAST
SUITE 1140
LOS ANGELES
CA
90067
US
|
Assignee: |
Daio Paper Corporation
|
Family ID: |
35462944 |
Appl. No.: |
11/597961 |
Filed: |
June 3, 2005 |
PCT Filed: |
June 3, 2005 |
PCT NO: |
PCT/JP05/10257 |
371 Date: |
November 29, 2006 |
Current U.S.
Class: |
604/358 ;
719/332 |
Current CPC
Class: |
D21H 17/14 20130101;
D21H 27/002 20130101; D21H 17/55 20130101; D21H 17/53 20130101;
A47K 2010/3266 20130101; D21H 21/24 20130101 |
Class at
Publication: |
604/358 ;
719/332 |
International
Class: |
D21H 27/00 20060101
D21H027/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 3, 2004 |
JP |
2004-165961 |
Nov 30, 2004 |
JP |
2004-347116 |
Claims
1. A sanitary thin paper which employs a pulp as a raw material and
contains a fatty acid ester-based compound and a fatty acid
amide-based compound and also contains a polyester-based
compound.
2. The sanitary thin paper according to claim 1 wherein the
softener components including said fatty acid ester-based compound
and said fatty acid amide-based compound are contained in an
amount, on dried mass basis, of 0.002 to 10 parts by mass per 100
parts by mass of said pulp raw material.
3. The sanitary thin paper according to claim 1 wherein said fatty
acid ester-based compound is contained internally and said fatty
acid amide-based compound is contained internally and/or
externally, and wherein a polyester-based compound is contained,
and said polyester-based compound is contained externally.
4. The sanitary thin paper according to claim 3 wherein a
polyester-based compound represented by General Formula (1):
##STR7## wherein R.sub.1 is HO-- or HO(R.sub.2O)a-, R.sub.2 is an
alkylene group having 2 to 3 carbon atoms, only a single type of
R.sub.2O may be present or two or more types of R.sub.2O are
attached randomly or as a block, "a" is 1 to 200, all "a"s may be
same or different in an identical molecule, b is 2 to 100, and
R.sub.3 is a hydrogen atom or a group represented by General
Formula (2): ##STR8## is contained as said polyester-based
compound.
5. The sanitary thin paper according to claim 3 or claim 4 wherein
said polyester-based compound is added in an amount, on dried mass
basis, of 0.05 to 30.0% by mass based on said pulp raw
material.
6. The sanitary thin paper according to claim 1 wherein the basis
weight (gsm) per 1 ply is 10 to 35 g/m.sup.2.
7. The sanitary thin paper according to claim 1 wherein a crepe is
formed at a paper making stage, and the crepe is formed in such a
shape that the apex distance in the machine direction of the crepe
is 0.1 mm or less, and the length in the width direction of the
crepe is 0.5 mm or less.
8. The sanitary thin paper according to claim 7 wherein the number
of the pulp fibers each of which has a distance of 1 .mu.m or more
from the adjacent pulp fiber in the section in the width direction
of the paper is 50% or more of the number of all pulp fibers.
9. The sanitary thin paper according to claim 7 or claim 8 wherein
the area ratio of the voids excluding the area occupied by the pulp
fibers in the width direction of the paper is 50% or more.
10. A process for producing a sanitary thin paper comprising adding
a fatty acid ester-based compound and a fatty acid amide-based
compound to a wet paper as a pulp raw material internally, and then
adding a polyester-based compound to said wet paper externally
on-line.
11. A process for producing a sanitary thin paper comprising adding
a fatty acid ester-based compound and a fatty acid amide-based
compound to a wet paper as a pulp raw material internally and/or
externally, and then adding externally on line a polyester-based
compound to said pulp wet paper or a dry paper obtained by drying
the same.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a sanitary thin paper for
example for a domestic use and a for producing the same, and
provides a particularly soft and smooth sanitary thin paper,
including tissue paper or toilet paper.
BACKGROUND OF THE INVENTION
[0002] In response to a recent change in life style, a trend toward
a soft and smooth sanitary thin paper becomes apparent in
consumers. Especially in the field of tissue paper, such a trend is
marked.
[0003] In order to ensure a softness, addition of a quaternary
ammonium salt is considered to be effective as disclosed in Patent
Reference 1. Also as disclosed in Patent Reference 2, a
polysiloxane substance is attempted to be added.
[0004] However, a comfortable texture to the touch can not be
obtained if only a softness is imparted but no smoothness is
associated. In order to obtain the "smoothness" by which the
texture is affected, it is proposed to add a lubricant, but it is
difficult to find a suitable lubricant.
[Patent Reference 1] Japanese Patent Publication No. 3180916
[Patent Reference 2] Japanese Patent Publication No. 2806974
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0005] A main objective of the invention is to provide a sanitary
thin paper which is highly excellent both in terms of softness and
smoothness as well as a process for producing the same.
Means to Solve the Problems
[0006] To solve the problems described above, the invention is
established as follows.
(Invention of claim 1)
[0007] A sanitary thin paper which employs a pulp as a raw material
and contains a fatty acid ester-based compound and a fatty acid
amide-based compound internally or externally.
(Invention of claim 2)
[0008] The sanitary thin paper according to claim 1 wherein the
softener components including said fatty acid ester-based compound
and said fatty acid amide-based compound are contained in an
amount, on dried mass basis, of 0.002 to 10 parts by mass per 100
parts by mass of said pulp raw material.
(Invention of claim 3)
[0009] The sanitary thin paper according to claim 1 or claim 2
wherein said fatty acid ester-based compound is contained
internally and said fatty acid amide-based compound is contained
either internally of externally, and wherein a polyester-based
compound is contained, and said polyester-based compound is
contained externally.
(Invention of claim 4)
[0010] The sanitary thin paper according to claim 3 wherein a
polyester-based compound represented by General Formula (1):
##STR1## wherein R.sub.1 is HO-- or HO(R.sub.2O)a-, R.sub.2 is an
alkylene group having 2 to 3 carbon atoms, only a single type of
R.sub.2O may be present or two or more types of R.sub.2O are
attached randomly or as a block, "a" is 1 to 200, all "a" s may be
same or different in an identical molecule, b is 2 to 100, and
R.sub.3 is a hydrogen atom or a group represented by General
Formula (2): ##STR2## is contained as said polyester-based
compound. (Invention of claim 5)
[0011] The sanitary thin paper according to claim 3 or claim 4
wherein said polyester-based compound is added in an amount, on
dried mass basis, of 0.05 to 30.0% by mass based on said pulp raw
material.
(Invention of claim 6)
[0012] The sanitary thin paper according to any one of claims 1 to
5 wherein the basis weight (gsm) per 1 ply is 10 to 35
g/m.sup.2.
(Invention of claim 7)
[0013] The sanitary thin paper according to any one of claims 1 to
6 wherein a crepe is formed at a paper making stage, and the crepe
is formed in such a shape that the apex distance in the machine
direction of the crepe is 0.1 mm or less, and the length in the
width direction of the crepe is 0.5 mm or less.
(Invention of claim 8)
[0014] The sanitary thin paper according to claim 7 wherein the
number of the pulp fibers each of which has a distance of 1 .mu.m
or more from the adjacent pulp fiber in the section in the width
direction of the paper is 50% or more of the number of all pulp
fibers.
(Invention of claim 9)
[0015] The sanitary thin paper according to claim 7 or 8 wherein
the area ratio of the voids excluding the area occupied by the pulp
fibers in the width direction of the paper is 50% or more.
(Invention of claim 10)
[0016] A process for producing a sanitary thin paper comprising
adding a fatty acid ester-based compound and a fatty acid
amide-based compound to a wet paper as a pulp raw material
internally, and then adding a polyester-based compound to said wet
paper externally on-line.
(Invention of claim 11)
[0017] A process for producing a sanitary thin paper comprising
adding a fatty acid ester-based compound and a fatty acid
amide-based compound to a wet paper as a pulp raw material
internally and/or externally, and then adding externally on line a
polyester-based compound to said pulp wet paper or a dry paper
obtained by drying the same.
Effects of the Invention
[0018] According to the invention, the excellence is experienced
not only in terms of softness but also in terms of smoothness. The
reasons for this excellence may be explained as described below.
Thus, since a fatty acid ester-based compound enters between fibers
to loosen the fibers, it gives a bulkiness, which is experienced as
a softness by a consumer. A fatty acid amide-based compound not
only serves to enhance the bulkiness but also gives a
moisture-retaining wetness/smoothness. Both of these fatty acid
ester-based compound and fatty acid amide-based compound are also
known to be preferable especially if they are cationic.
[0019] When such a pulp paper is combined externally with a
polyester-based compound, a thin film of the polyester can be
formed on the surface of the pulp fiber, which serves to reduce the
friction between fibers on a superficial layer upon touch to a
skin. Accordingly, a resultant sanitary thin paper is porous,
moistening, soft, and its surface is smooth.
[0020] As described above, it is preferable to add a
polyester-based compound externally since a thin polyester film is
intended to be formed on the pulp fiber surface. A fatty acid
ester-based compound is added internally since it is intended to
enter between the fibers to loosen the inter-fiber binding. On the
contrary, a fatty acid amide-based compound may be added
externally, although it exerts a higher effect when added
internally.
[0021] On the other hand, the smoothness was found to be related
greatly to the crepe morphology. Thus, as shown in FIG. 1, it was
found to be preferable that the apex distance L in the machine
direction of the crepe (paper) is 0.1 mm or less, and the widthwise
length W of the crepe is 0.5 mm or less. An apex distance L of the
machine direction of the crepe which is short and 0.1 mm or less
gives a smoothness. On the other hand, a widthwise length W of the
crepe exceeding 0.5 mm the smoothness upon wiping a skin with a
sanitary thin paper while moving in the machine direction is
affected adversely.
BEST MODE FOR CARRYING OUT THE INVENTION
[0022] The embodiments of the invention are described below. Also
as discussed above, a sanitary thin paper may for example be a
tissue paper or a toilet paper. It may be used as a cosmetic
paper.
[0023] When as an inventive sanitary thin paper one having a basis
weight (gsm, JIS P 8124) per 1 ply of 7 to 40 g/m.sup.2 (preferably
10 to 35 g/m.sup.2, more preferably 11.0 to 17.0 g/m.sup.2) is
employed the characteristics of the invention are exerted
favorably. A weight less than 7 g/m.sup.2 leads to a difficulty in
paper making, and a weight less than 10 g/m.sup.2 results in a too
thin paper which may undergo problematic perforation at a stage of
paper making. On the other hand, a weight exceeding 40 g/m.sup.2
results in a too thick and hard paper, and a weight exceeding 35
g/m.sup.2 results in a coarse crepe, if made, on the paper,
yielding a poor surface. Accordingly, the effect of a softener
becomes difficult to be exerted. An inventive sanitary thin paper
may be of 2-ply (two sheets make a unit) or 3-ply or more. While
the invention exerts an especially marked effect when it is a
tissue paper which should have a necessary paper strength, it may
be a toilet paper.
[0024] An inventive sanitary thin paper can be produced by a known
facility and a known process. Thus, a pulp raw material may be
subjected to a paper making machine followed preferably by a crepe
treatment or calender treatment.
[0025] An inventive sanitary thin paper in this embodiment employs
as a softener for a sanitary thin paper a polyester-based compound
represented by General Formula (1), which is added to a pulp raw
material.
[0026] While a polyester-based compound can be dissolved or
dispersed in water since it is water-soluble, it is used preferably
as being dissolved in a solvent such as isopropyl alcohol or
dipropylene glycol because of its high molecular weight.
[0027] A polyester-based compound represented by General Formula
(1) can be produced by a known process from an aromatic
dicarboxylic acid or its derivative and a glycol represented by
General Formula HO--(R.sub.2O) a-H. Such an aromatic dicarboxylic
acid may for example be a phthalic acid such as terephthalic acid
and isophthalic acid, and its derivative may for example be a lower
alkyl ester of such a dicarboxylic acid, including dimethyl ester,
diethyl ester, dipropyl ester and dibutyl ester, a chloride of such
a dicarboxylic acid, and also a phthalic anhydride. Any one of such
aromatic dicarboxylic acids or their derivatives may be used, or a
mixture of two or more may be used.
[0028] A glycol represented by General Formula HO--(R.sub.2O) a-H
may for example be ethylene glycol, propylene glycol, diethylene
glycol, dipropylene glycol, polyethylene glycol, polypropylene
glycol, a random or block copolymer of propylene oxide with
ethylene oxide having hydroxyl groups at both ends.
[0029] Any one of such glycols may be used or a mixture of two or
more may be used. In General Formula (1), "a" is 1 to 200, more
preferably 1 to 150. An "a" exceeding 200 results in a too high
viscosity of the polyester-based compound represented by General
Formula (1), which may lead to a difficulty in handling. In General
Formula (1), all "a" s may be same or different in an identical
molecule. A polyester-based compound represented by General Formula
(1) in which all "a" s are same can be produced for example by
reacting a dimethyl ester of terephthalic acid, isophthalic acid,
phthalic acid and the like with a polyethylene glycol having a
certain molecular weight and conducting an transesterification
reaction accompanied with de-methanol reaction. A polyester-based
compound represented by General Formula (1) in which a repeating
unit having "a" of 1 and a repeating unit having "a" of several
tens to a hundred and several tens can be produced for example by
reacting a dihydroxy ester of terephthalic acid, isophthalic acid,
phthalic acid and the like with a polyethylene glycol having a
certain molecular weight and conducting an transesterification
reaction accompanied with de-ethylene glycol reaction. In General
Formula (1), "b" is 2 to 100, more preferably 2 to 30. A "b"
exceeding 100 results in a too high viscosity of the
polyester-based compound represented by General Formula (1), which
may lead to a difficulty in handling.
[0030] The weight mean molecular weight of a polyester-based
compound represented by General Formula (1) is preferably 1,000 to
200,000, more preferably 10,000 to 50,000. A weight mean molecular
weight of a polyester-based compound less than 1,000 may lead to an
insufficient softness imparting effect. A weight mean molecular
weight of a polyester-based compound exceeding 200,000 may result
in a too high viscosity of the polyester-based compound, which may
lead to a difficulty in handling. The weight mean molecular weight
of a polyester-based compound can be determined by a gel permeation
chromatography using a monodisperse polyethylene glycol having a
known molecular weight.
[0031] While in an inventive sanitary thin paper a polyester-based
compound represented by General Formula (1) may be added at a
content (in an amount to be added) which is not limited
particularly, preferably it is added externally in an amount, on
dried mass basis, of 0.05 to 30.0% by mass based on said pulp raw
material, more preferably 0.5 to 5.0% by mass. An amount of the
polyester-based compound represented by General Formula (1) less
than 0.05% by mass may lead to an insufficient softness imparting
effect. An amount of the polyester-based compound represented by
General Formula (1) exceeding 30.0% by mass results in a higher
softness imparting effect, but also poses a problem including
stickiness.
[0032] The invention may contain a water-soluble polyurethane resin
represented by General Formula (3) if necessary. Such a
water-soluble polyurethane resin can be added in an amount, on
dried mass basis, of 0.05 to 7% by mass based on the pulp raw
material. The weight ratio of a polyester-based compound and the
water-soluble polyurethane resin is 100/1 to 55/45, preferably
100/1 to 70/30. Thus, one whose major component is an inventive
polyester-based compound is preferred. The process for addition may
be an external procedure such as spray application, offset
application and the like. ##STR3## wherein R.sub.1 is a
polyalkylene ether glycol chain having a molecular weight of 400 to
5000, R.sub.2 is the formulae: ##STR4## and Z is an integer of 3 to
300.
[0033] In the invention, the addition of a polyester-based compound
mentioned above enables an addition to pulp fibers while not being
affected by the hydrogen bond of the pulp raw material, possibly
undergoing coating on each pulp fiber, resulting in a
smoothness.
[0034] In the invention, it is preferred to add as fatty acid
ester-based compounds both of cationic fatty acid ester-based
compounds and anionic fatty acid ester-based compounds. In
addition, (a) either one or both of these fatty acid ester-based
compounds are added internally, (b) a fatty acid amide-based
compound is added internally or externally. The addition of an
additive may be accomplished externally, for example by spray
application, offset application and the like. On the other hand, an
internal addition, thus, mixing into a paper making raw material
prior to the paper making may be employed.
[0035] A chemical solution may be added in an amount, on dried mass
basis, of 0.002 to 10 parts by mass per 100 parts by mass of said
pulp raw material. The ratio of (a)/(b) is preferably 0.1 to
500.
[0036] A fatty acid ester-based compound of (a) permeates into a
fiber when depositing onto the fiber to allow for a hydrogen bond
between the insides of the lumens (voids) upon drying whereby
preventing a crash, resulting in a further bulky soft paper.
Nevertheless, in the absence of the cationic property, it is not
fixed readily in a fiber by itself, posing a difficulty in exerting
its effect.
[0037] A fatty acid ester-based compound may for example be a
compound made from a C6-C24 alcohol and a C7-C25 fatty acid. Such a
C6-C24 alcohol may be a straight alcohol, branched alcohol,
saturated alcohol and unsaturated alcohol. Among these various
alcohols, a C10-22 alcohol is preferred, with lauryl alcohol,
myristyl alcohol, cetyl alcohol, stearyl alcohol, behenyl alcohol
and oleoyl alcohol being particularly preferred. Any one of such
alcohol may be used, or a mixture of two or more may be used.
[0038] A fatty acid amide-based compound of (b) coats the surface
of each individual fiber to impart a bulkiness together with a
lubricity on the surface, whereby improving the paper surface
smoothness.
[0039] An inventive fatty acid amide compound can be obtained by
reacting a polyalkylene polyamine and a carboxylic acid.
[0040] A polyalkylene polyamine employed in the invention contains
at least three amino groups in its molecule and is represented by
the following formula:
H.sub.2N--(R.sup.1--NH--).sub.n--R.sup.1--NH.sub.2 (4) wherein each
R.sup.1 is independently a C1-4 alkylene group, and n is an integer
of 1 to 3.
[0041] Examples of R.sup.1 in Formula (4) shown above are methylene
group, ethylene group, trimethylene group, tetramethylene group and
butylene group. Different R.sup.1s may be present in one molecule,
and two or more polyalkylene polyamines may be employed. A
preferred R.sup.1 is an ethylene group. A number of carbons in the
alkylen group exceeding 4 leads to a difficulty in handling. If an
amide compound obtained from such a compound is used, a bulky and
soft paper can be employed.
[0042] A carboxylic acid employed in the production of an amide
compound is a C10-24 carboxylic acid. Such a carboxylic acid may be
a saturated carboxylic acid, unsaturated carboxylic acid, straight
carboxylic acid or branched carboxylic acid. Nevertheless, at least
40% by mass should correspond to a carboxylic acid having at least
either one of an unsaturated bond or a branched chain.
[0043] A C10-24 carboxylic acid may for example be any of following
compounds: a single fatty acid such as capric acid, lauric acid,
myristic acid, palmitic acid, palmitoleic acid, isopalmitic acid,
stearic acid, oleic acid, linolic acid, linoleic acid, isostearic
acid, arachic acid, behenic acid, erucic acid, lignoceric acid and
the like; and a natural fat-derived mixed fatty acid such as
coconut oil fatty acid, palm oil fatty acid, beef tallow fatty
acid, lard fatty acid, soybean oil fatty acid, rapeseed oil fatty
acid, toll oil fatty acid, olive oil fatty acid, cocoa butter fatty
acid, sesame oil fatty acid, corn oil fatty acid, sunflower oil
fatty acid, cotton seed oil fatty acid and the like, as well as
hydrogenated derivatives thereof. Any one of these may be used
alone, or a mixture of two or more may be used. Among these, a
C12-22 carboxylic acid is preferred, with a C14-C18 carboxylic acid
being preferred especially. A carboxylic acid having less than 10
carbon atoms yields an amide compound which shows only a poor
bulkiness and softness improving effect, while one whose number of
carbons exceeds 24 may lead to a difficulty in handling of
resultant amide compound.
[0044] Among those listed above, an unsaturated bond-carrying
carboxylic acid (single fatty acid) may for example be oleic acid,
linolic acid, linoleic acid, erucic acid and palmitoleic acid, and
a branched chain-carrying carboxylic acid may be isopalmitic acid
and isostearic acid. Any of these fatty acid may contain other
fatty acids as impurities, and such fatty acid can also be
employed. A natural mixed fatty acid containing 40 to 100% by mass
of unsaturated carboxylic acids may for example be a soybean oil
fatty acid, palm oil fatty acid, olive oil fatty acid, cocoa butter
fatty acid, sesame oil fatty acid, corn oil fatty acid, sunflower
oil fatty acid, cotton seed oil fatty acid, beef tallow fatty acid,
lard fatty acid and the like. Among the carboxylic acids having at
least either one of unsaturated bonds and branched chains or
mixtures thereof, those especially preferred are soybean oil fatty
acid, oleic acid and erucic acid.
[0045] A fatty acid amide-based compound in this embodiment can be
obtained by reacting a polyalkylene polyamine represented by
Formula (4) shown above with a carboxylic acid mentioned above.
Such a carboxylic acid is employed in an amount of 1.5 to 2.5
moles, preferably 1.8 to 2.2 moles per 1 mole of a polyalkylene
polyamine. An amount less than 1.5 moles makes it impossible to
obtain a sufficiently bulky soft paper, while an amount exceeding
2.5 moles leads to a difficulty in handling of the resultant amide
compound.
[0046] While an amide compound described above can be used as it is
as an additive, it can be handled more easily when used as a salt
by neutralizing with an inorganic acid or organic acid. Such an
inorganic acid may for example be hydrochloric acid, sulfuric acid,
carbonic acid, nitric acid, phosphoric acid and the like. Examples
of the organic acid are formic acid, acetic acid, propionic acid,
octylic acid, butyric acid, oxalic acid, malonic acid, itaconic
acid, adipic acid, succinic acid, sebacic acid, citric acid,
hydroxybenzoic acid, malic acid, hydroxymalonic acid, lactic acid,
salicylic acid, hydroxyvaleric acid, aspartic acid, glutamic acid,
taurine, sulfamic acid, lauric acid, myristic acid, palmitic acid,
stearic acid, oleic acid and the like. Among these, organic acids
are preferred, with formic acid, acetic acid and lactic acid being
particularly preferred.
[0047] The amount of an acid to form a salt can be selected
appropriately depending on the purpose by measuring the entire
amine value of a product obtained by the reaction described above.
Preferably, an inorganic acid or an organic acid equivalent to the
entire amine value is added to form a salt of the amide
compound.
[0048] An amide compound thus obtained or a salt thereof can easily
be handled, and can produce a bulky soft paper. Also when adding
this compound to a pulp slurry formed by dispersing a pulp fiber in
water at a certain rate, foaming can advantageously be
inhibited.
[0049] Since the use of a chemical solution may reduce the paper
strength, it is preferable that a paper strength agent such as a
starch, polyacrylamide-based superficial paper strength agent, a
polyvinyl alcohol and the like is added internally, with a starch
being preferred especially.
[0050] While in this embodiment a fatty acid ester-based compound
and a fatty acid amide-based compound are added internally to a
pulp wet paper to which then a polyester-based compound is added
online externally or a fatty acid ester-based compound and a fatty
acid amide-based compound are added internally and/or externally
and then a polyester-based compound is added online externally to a
pulp wet paper or dry paper, other appropriate moisturizing agent
or lubricant can be added in a separate step.
[0051] Such a moisturizing agent may for example be polyethylene
glycol, glycerin, 1,3-butylene glycol, 1,2-pentanediol, erythritol,
sorbitol, xylitol, maltitol, propylene glycol, dipropylene glycol,
diglycerin, sodium pyrrolidone carboxylate, lactic acid, sodium
lactate and the like.
[0052] A lubricant may for example be a polysiloxane such as
silicone oil, silicone powder and the like. If necessary, a
polyester-based compound described above can be converted into a
microparticle for example by means of emulsification whereby being
used as a powder particle. A silicone powder consisting of powder
particles whose mean particle size is 0.1 to 30 .mu.m is especially
preferred. Alternatively, an aggregated powder of the powder
particle mentioned above whose mean particle size is 10 to 100
.mu.m is also preferred.
[0053] As a pulp raw material for an inventive sanitary thin paper,
a pulp fiber whose NBKP content is 30 to 80% by mass and whose LBKP
is 20 to 70% by mass is employed preferably in a major part. While
the pulp raw material can contain 30% by mass or less, preferably
10% by mass or less of an waste paper pulp if necessary, one
containing 100% by mass of virgin pulp is more preferable in view
of softness and the like.
[0054] On the other hand, a sanitary thin paper in this embodiment
has an area ratio of the void excluding the area occupied by a pulp
fiber F in the widthwise section of a paper shown schematically in
FIG. 2 (thus an area ratio of the non-hatched region excluding a
pulp fiber F in a unit area S in FIG. 2) which is 50% or more. A
higher area ratio results in a softer touch. An excessively high
area ratio results in a reduced strength and a reduced
firmness.
[0055] Particularly, the number of the pulp fibers each of which
has a distance of 1 .mu.m or more from the adjacent pulp fiber in
the section in the width direction of the paper is 50% or more of
the number of all pulp fibers. And most preferably the number of
those of 5 .mu.m or more is 50% or more. Similarly in this case a
higher rate of the number results in a softer touch. An excessively
high rate of the number results in a reduced strength.
[0056] As discussed in Examples shown below, no conventional
examples involve a product having a morphology according to the
invention.
[0057] An MMD as an index of the surface characteristics are
preferably 9.0 or less, especially 8.5 or less for a tissue paper,
and 13 or less, especially 11 or less for a toilet paper.
[0058] In a test for such surface characteristics, a frictional
texture tester KESSE manufactured by KATO TECH CO., LTD. can be
employed. For the measurement, as shown in FIG. 3, a friction probe
consisting of a piano wire of 0.5 mm in diameter and having a
contact length of 5 mm was brought into contact with a paper sample
under a load of 10 g while applying to the paper sample a tension
of 20 g/cm in the direction of the movement with moving over a
distance of 2 cm at a rate of 0.1 cm/sec whereby measuring a
friction coefficient. The mean deviation of the friction
coefficient (the change in the surface thickness by the movement of
the friction probe, thus, the friction coefficient divided by the
friction distance (movement distance=2 cm)) is designated as
MMD.
[0059] A softness of 1.5 or less, especially 1.4 or less for a
tissue paper, and 3.5 or less, especially 2.5 or less for a toilet
paper is preferred.
[0060] In order to obtain a sanitary thin paper in this embodiment,
various factors may be selected. Thus, the ratio between LBKP and
NBKP as pulp raw material, the types of the pulps (fiber
coarseness, types and ages of source wood materials and the like),
freeness, paper moisture, calender gap/pressure/material, chemical
solution addition and its quantity and the like may vary
appropriately. Preferably, the pulp contains no waste pulp.
[0061] In addition, tensile strength, aspect ratio, crepe
morphology (crepe rate, crepe height), moisture content, density,
addition of paper strengthening agents, addition of chemical
solutions as well as their quantities may also vary appropriately.
Desired surface characteristics can be obtained also by varying
pulp incorporation, calender condition, paper moisture, doctor
blade tip angle, blade angle, balance between adhesion/peeling
strength, crepe rate, addition of chemical solutions and their
quantities and the like appropriately.
[0062] In obtaining a crepe morphology according to the invention,
the effects of the addition of the additives are of important.
Thus, it is preferable to add both of a cationic fatty acid
ester-based compound (chemical solution) and an anionic fatty acid
ester-based compound (chemical solution).
[Softener component]
[0063] A softener component including a fatty acid ester-based
compound and a fatty acid amide-based compound is discussed
below.
[0064] A softener added to a sanitary thin paper is preferably a
cationic surfactant. Such a cationic surfactant is not limited
particularly, and preferably an amine compound having in its
molecule at least one C6-26 saturated or unsaturated hydrocarbon
group or a neutralized or quaternized derivative thereof as well as
a mixture thereof. More specifically, such a preferred amine
compound or a neutralized or quaternized derivative thereof has in
its molecule at least one, preferably one or two, most preferably
two C6-26, preferably C14-22 saturated or unsaturated hydrocarbon
group such as an alkyl or alkenyl group. Such a hydrocarbon group
may have in its chain an ester group, reversed ester group, amide
group, reversed amide group, ether group. Such a hydrocarbon group
can be introduced for example by using a fatty acid obtained by
hydrogenating or partially hydrogenating a beef tallow-derived
non-hydrogenated fatty acid or unsaturated moiety employed usually
in an industrial field, a fatty acid or a fatty acid ester obtained
by hydrogenating or partially hydrogenating a plant-derived
non-hydrogenated fatty acid or fatty acid ester or unsaturated
moiety derived from palm or coconut.
[0065] In addition, a compound represented by General Formula (5):
##STR5## wherein R.sup.3 is a C6-24 alkyl group or a C6-24 alkenyl
group, each of R.sup.4 and R.sup.5 is one selected from
(EO).sub.m(PO).sub.nH, a C1-24 alkyl group and a C1-24 alkenyl
group, and R.sup.4 and R.sup.5 are same or different, X.sup.- is an
anion, wherein E is an ethylene group and P is a propylene group,
and the total of m and n is 1 to 60, where m and n denote mean
addition mole numbers, is also employed preferably.
[0066] Particularly contemplated here is a C6-24 alkyl
group-carrying trimethylmonoalkylammonium halide and/or a C6-24
alkyl group-carrying dimethyldialkylammonium halide.
[0067] Also contemplated is an alkyl group and/or an alkenyl
group-carrying imidazoline ring-carrying quaternary ammonium salt.
Such an imidazoline ring-carrying quaternary ammonium salt may be a
compound represented by General Formula (6): ##STR6## wherein
R.sup.6 is a C6-24 alkyl group or a C6-24 alkenyl group, R.sup.7 is
a C1-24 alkyl group or a C1-24 alkenyl group and X.sup.- is an
anion.
[0068] In the invention, an alkoxylated fatty acid ester can be
employed.
[0069] A cationic surfactant which can be employed in the invention
may also be an alkylammonium salt represented by R1R2R3R4N+X-,
wherein R1 is selected from an alkyl group having about 12 to about
18 carbon atoms, or an aromatic aryl or alkaryl group having about
12 to about 18 carbon atoms; each of R2, R3 and R4 is independently
of one another selected from a hydrogen atom, an alkyl group having
about 1 to about 18 carbon atoms, or an aromatic aryl or alkaryl
group having about 12 to about 18 carbon atoms; X is an anion
selected from chloride, bromide, iodide, acetate, phosphate,
nitrate, sulfate, methyl sulfate, ethyl sulfate, tosylate, lactate,
glycolate as well as mixtures thereof. The alkyl group may contain
an ether bond or hydroxy or amino group-substituted form (for
example, the alkyl group can contain polyethylene glycol and
polypropylene glycol moieties).
[0070] Another useful cationic surfactant is an aminoamide in which
R1 in the structure shown above is converted into
R5CO--(CH.sub.2).sub.n-- wherein R5 is an alkyl group having about
12 to about 18 carbon atoms; n is an integer of about 2 to about 6,
preferably about 2 to about 4, more preferably about 2 to about 3).
Non-limiting examples of such a cationic emulsifier are stearamide
propyl PG-dimonium chloride phosphate, stearamide propylethyl
dimonium ethosulfate, stearamide propyldimethyl (myristyl acetate)
ammonium chloride, stearamide propyldimethyl cetearyl ammonium
tosylate, stearamide propyldimethyl ammonium chloride, stearamide
propyldimethyl ammonium lactate as well as mixtures thereof.
[0071] Non-limiting examples of a quaternary ammonium salt cationic
surfactant are cetylammonium chloride, cetylammonium bromide,
laurylammonium chloride, laurylammonium bromide, stearylammonium
chloride, stearylammonium bromide, cetyldimethyl ammonium chloride,
cetyldimethyl ammonium bromide, lauryldimethyl ammonium chloride,
lauryldimethyl ammonium bromide, stearyldimethyl ammonium chloride,
stearyldimethyl ammonium bromide, cetyltrimethyl ammonium chloride,
cetyltrimethyl ammonium bromide, lauryltrimethyl ammonium chloride,
lauryltrimethyl ammonium bromide, stearyltrimethyl ammonium
chloride, stearyltrimethyl ammonium bromide, lauryldimethyl
ammonium chloride, stearyldimethylditallow dimethyl ammonium
chloride, dicetylammonium chloride, dicetylammonium bromide,
dilaurylammonium chloride, dilaurylammonium bromide,
distearylammonium chloride, distearylammonium bromide,
dicetylmethyl ammonium chloride, dicetylmethyl ammonium bromide,
dilaurylmethyl ammonium chloride, dilaurylmethyl ammonium bromide,
distearylmethyl ammonium chloride, distearylmethyl ammonium bromide
as well as mixtures thereof.
[0072] An additional quaternary ammonium salt is one whose C12-C22
alkyl carbon chain is derived from a tallow fatty acid or coconut
fatty acid. The term "tallow" generally means an alkyl group
derived from a tallow fatty acid in which C12-C18 alkyl chains
coexist (usually a hydrogenated tallow fatty acid) . The term
"coconut" generally means an alkyl group derived from a coconut
fatty acid in which C12-C18 alkyl chains coexist (usually a
hydrogenated tallow fatty acid). Examples of a quaternary ammonium
salt derived from the tallow and coconut origins are ditallow
dimethyl ammonium chloride, ditallow dimethyl ammonium methyl
sulfate, di(hydrogenated tallow) dimethyl ammonium chloride,
di(hydrogenated tallow) dimethyl ammonium acetate, ditallow
dipropyl ammonium phosphate, ditallow dimethyl ammonium nitrate,
di(coconut alkyl) dimethyl ammonium chloride, di(coconut alkyl)
dimethyl ammonium bromide, tallow ammonium chloride, coconut
ammonium chloride, stearamide propyl PG-dimonium chloride
phosphate, stearamide propylethyl dimonium ethosulfate, stearamide
dimethyl (myristyl acetate) ammonium chloride, stearamide
dipropylmethyl cetearylammonium tosylate, stearamide dimethyl
ammonium chloride, stearamide dimethyl ammonium lactate as well as
mixtures thereof.
[0073] A preferable cationic surfactant useful here includes
dilauryl dimethyl ammonium chloride, distearyl dimethyl ammonium
chloride, dimyristyl dimethyl ammonium chloride, dipalmityl
dimethyl ammonium chloride, distearyl dimethyl ammonium chloride,
as well as mixtures thereof.
[0074] Otherwise, a softener may for example be a polyethylene
polyamine higher fatty acid amide-type cationic surfactant,
imidazoline-type cationic surfactant and a quaternary ammonium
salt-type cationic surfactant such as an alkyldimetyl ammonium
chloride, with a polyethylene polyamine higher fatty acid
amide-type cationic surfactant being preferred especially because
of a higher softening effect.
[0075] Such a polyethylene polyamine higher fatty acid amide-type
cationic surfactant may for example be a polyethylene polyamine
higher fatty acid amide (e1), a polyoxyalkylene polyethylene
polyamine higher fatty acid amide (e2), a polyethylene polyamine
higher fatty acid amide urea condensate (e3), a polyoxyalkylene
polyethylene polyamine higher fatty acid amide urea condensate
(e4), (e1) to (e4) epichlorohydrin adduct (e5), a polyethylene
polyamine higher fatty acid amide alkyl chloride quaternized salt
(e6), a polyethylene polyamine higher fatty acid amide
monochloroacetic acid adduct amphoteric compound (e7) and a
polyethylene polyamine higher fatty acid amide partial
imidazolinium salt (e8) and the like.
[0076] A polyethylene polyamine as a constituent of these (e1) to
(e8) may for example be diethylene triamine, triethylene tetramine,
tetraethylene pentamine and the like. Among these, diethylene
triamine and triethylene tetramine are preferred.
[0077] A polyoxyalkylene group constituting (e2) or (e4) is a group
to which an alkylene oxide is added. Such an alkylene oxide may for
example be ethylene oxide, propylene oxide and butylene oxide.
Among these, ethylene oxide and a combination of ethylene oxide
with propylene oxide (block or random addition) are preferred. The
mixing weight ratio when using a combination of ethylene oxide with
propylene oxide is preferably 1:(0.1 to 1.0). The molar number of
the alkylene oxide to be added is usually 1 to 10 moles, preferably
1 to 5 moles.
[0078] While a higher fatty acid as a constituent of these (e1) to
(e8) is usually one derived from a natural fatty acid such as a
palm oil, beef tallow, rapeseed oil, rice bran oil, fish oil and
the like, a synthetic higher fatty acid produced by a petroleum
chemical process may also be employed. Among these, a higher fatty
acid having an iodine value of 50 or less and 12 to 24 carbon atoms
is preferred.
[0079] Another constituent of these (e1) to (e8), namely a
polyethylene polyamine or a polyoxyalkylene polyethylene polyamine
is present in a molar ratio to a higher fatty acid usually of 1:1.0
to 2.5, preferably 1:1.2 to 1.8. Among (e1) to (e8) listed above,
those preferred are (e1) to (e5).
EXAMPLES
[0080] Examples of the invention are described below.
[0081] Samples for a tissue paper and a toilet paper were evaluated
while comparing between the types of additives added. The results
are shown in Table 1. The additives employed were included in Table
1.
[0082] The evaluation was made by measuring an MIU value related to
the friction coefficient using a KES test machine manufactured by
KATO TECH CO., LTD. A smaller value reflects a smoother
texture.
[0083] Also under an electron microscope observation, the fiber
fluffiness on the surface of the paper was observed, since only MIU
values are insufficient for the evaluation.
[Table 1]
[0084] Based on these results, an inventive product was evaluated
in a sensory test to be excellent both in terms of "softness" and
"smoothness". A total fluff length of 0.1 mm or longer and a large
total number of fluffs of 0.1 mm or longer, as observed here,
reflect a higher smoothness. This is because of the presence of a
large number of long fluffs on the paper surface, as assumed from
the fluffs illustrated.
Example 2
[0085] A commercially available tissue paper and an inventive
tissue paper were compared in various profiles. Each was tested as
a 2-ply (two sheets make a unit) sample. The results are shown in
Table 2.
[0086] The softener employed here are listed below. The results are
shown in Table 2.
[0087] The softener employed here are listed below. Softener A:
Nonionic fatty acid ester (NIPPON PMC, SFS1001) Softener B:
Cationic fatty acid ester (NIPPON PMC, SFS1002) Softener C:
Cationic fatty acid ester (NIPPON PMC, SFS1004) Softener D:
Cationic fatty acid amide (NOF, bulk agent J)
[0088] The sensory test was on the basis of 5-point evaluation. A %
void area and a % fiber number were measured by stacking 6 samples
whose top and bottom were covered with OHP sheets, which was cut by
a sharp shaving blade at an angle of 90.degree., and the sectional
view of a sample after cutting was taken as a .times.1000 SEM
photograph, which was then evaluated.
[Table 2]
[0089] Based on these results, an inventive product was evaluated
in a sensory test to be excellent both in terms of "softness" and
"smoothness".
[0090] The invention can be applied as a sanitary thin paper for
example for a domestic use including tissue paper or toilet paper
and a process for producing the same, especially as a soft and
smooth sanitary thin paper.
BRIEF DESCRIPTION OF THE DRAWINGS
[0091] FIG. 1 shows a schematic view of a crepe in a sanitary thin
paper, (a) a surface, (b) a B-B view on arrow.
[0092] FIG. 2 is a widthwise sectional view of a paper.
[0093] FIG. 3 is a schematic view of an MMD testing process.
TABLE-US-00001 TABLE 1 Exper- Exper- Exper- Exper- Exper- Exper-
Unit iment 1 iment 2 iment 3 iment 4 iment 5 iment 6 Internal Basis
weight (gsm) g/m.sup.2 12.0 15.0 16.0 21.0 12.0 21.0 addition Fatty
acid ester-containing softener (SEIKO % 0.1 0.1 0.1 0.1 0.1 0.1 PMC
CORPORATION, TFS301) Fatty acid amide-containing softener (NOF, %
0.08 0.08 0.08 0.08 0 0 DZ2220) Wet paper strengthening agent
(SEIKO PMC % 0.6 0.6 0.1 0.1 0.6 0 CORPORATION, WS547) Wet paper
Polyester-based compound (NICCA % 0.1 0.1 0.9 0.1 0 0.1 external
CHEMICAL, (*A-POLE*) ES-500) addition Evaluation Smoothness (MIU
vertical) 0.9 0.8 0.7 1.2 1.0 1.5 Smoothness (MIU lateral) 0.7 0.6
0.7 0.9 0.9 1.3 Total length of fluffs of 0.1 mm or longer Mm/m 250
350 250 300 150 100 Total number of fluffs of 0.1 mm or longer
Fluffs/m 2000 2800 2000 2400 1200 800
[0094] TABLE-US-00002 TABLE 2 Exper- Exper- iment iment 13 14
Experiment Experiment Com- Com- 11 12 pany B pany C Exper-
Applicant Company A Com- Com- Exper- Exper- Exper- Exper- Exper-
iment Commercial Commercial mercial mercial iment iment iment 7
iment 8 iment 9 10 product product product product 15 16 Softener
component Type A + D A + D A + D A + D C D Unit weight (gsm)
g/m.sup.2 11.0 11.0 11.0 11.0 11.3 11.2 10.7 10.9 11.0 11.0
Softness mm 1.31 1.26 1.24 1.32 1.50 1.54 1.50 1.54 1.42 1.44 MMD
mm 8.4 8.1 7.8 8.2 9.3 9.1 9.4 9.5 9.3 8.9 Crepe Longitudinal mm
0.09 0.08 0.07 0.10 0.29 0.15 0.25 0.14 0.13 0.14 inter-apex
distance Widthwise mm 0.47 0.45 0.46 0.48 1.31 0.48 1.03 0.81 0.52
0.51 length Void area ratio % 53 55 55 51 45 19 41 21 48 41 Number
ratio % 52 53 54 50 30 15 8 14 47 40 Sensory Softness 5 5 5 5 3 3 2
3 4 3 evaluation Smoothness 5 5 5 5 3 3 2 3 3 4
* * * * *