Breathable film and process for production of the same

A breathable film and a process for producing the same are disclosed, the breathable film comprising a resin composition comprising (1) 100 parts by weight of a linear low-density polyethylene resin having a density of from 0.870 to 0.915 g/cm.sup.3 and containing from 15 to 50% by weight of a component which is extractable with xylene at room temperature and which has a weight average molecular chain length of from 1,000 to 9,000 .ANG.; (2) from 50 to 400 parts by weight of a filler; and optionally, (3) from 0.5 to 8 parts by weight of a nonionic surface active agent. The breathable film of the invention not only has excellent film moldability and film stretchability but also shows high breathability, good touch and appearance, and high strength.

FIELD OF THE INVENTION 
The present invention relates to a breathable film and a process for 
production of the same. More particularly, it is concerned with a 
breathable film made of a resin composition containing a specified 
polyethylene resin as a resin component, which shows high breathability, 
good touch and appearance, and high strength as well as a process for the 
production of the same. 
BACKGROUND OF THE INVENTION 
It is known as described, for example, in Japanese Patent Application (OPI) 
NO. 149303/83 (the term "OPI" as used herein refers to a "published 
unexamined Japanese patent application") that breathable films which are 
permeable to gases such as water vapor but not to liquids such as water 
are obtainable by stretching films made of resin compositions comprising a 
resin, a filler, and so forth. In order to obtain films having high 
breathability, it is necessary to increase the proportion of the filler in 
the resin composition or to increase the stretch ratio. 
These techniques to increase the breathability, however, decrease film 
moldability and the strength of formed films and, thus, are limited in 
their use. Accordingly, films having excellent film moldability and good 
film strength as well as high breathability cannot be obtained by these 
techniques. Another technique to increase the breathability wherein films 
are stretched at low temperatures has a disadvantage in that the resulting 
breathable films have poor touch and appearance. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide a breathable film which 
has not only excellent film moldability and film stretchability but also 
high breathability, good touch and appearance, and high strength. 
Another object of the present invention is to provide a process for 
producing the above-described breathable film. 
More specifically, in one embodiment of the present invention, it relates 
to a breathable film made of a resin composition comprising (1) 100 parts 
by weight of a linear low-density polyethylene resin having a density of 
from 0.870 to 0.915 g/cm.sup.3 and containing from 15 to 50% by weight of 
a component which is extractable with xylene at room temperature and which 
has a weight average molecular chain length of from 1,000 to 9,000 .ANG.; 
and (2) from 50 to 400 parts by weight of a filler. 
In another embodiment, the present invention relates to a breathable film 
made of a resin composition comprising (1) 100 parts by weight of a linear 
low-density polyethylene resin having a density of from 0.870 to 0.915 
g/cm.sup.3 and containing from 15 to 50% by weight of a component which is 
extractable with xylene at room temperature and which has a weight average 
molecular chain length of from 1,000 to 9,000 .ANG.; (2) from 50 to 400 
parts by weight of a filler; and (3) from 0.5 to 8 parts by weight of a 
nonionic surface active agent. 
In a further embodiment, the present invention relates to a process for 
producing a breathable film comprising uniaxially stretching a film made 
of a resin composition comprising (1) 100 parts by weight of a linear 
low-density polyethylene resin having a density of from 0.870 to 0.915 
g/cm.sup.3 and containing from 15 to 50% by weight of a component which is 
extractable with xylene at room temperature and which has a weight average 
molecular chain length of from 1,000 to 9,000 .ANG.; and (2) from 50 to 
400 parts by weight of a filler, at a temperature of from 30.degree. to 
80.degree. C. at a stretch ratio of from 1.2 to 8 in the mechanical 
direction, or biaxially stretching said film at a temperature of from 
40.degree. to 100.degree. C. at a stretch ratio of from 1.1 to 8.0 in the 
mechanical direction and then at a temperature of from 70.degree. to 
100.degree. C. at a stretch ratio of not higher than 6.0 in the transverse 
direction. 
In a still further embodiment, the present invention relates to a process 
for producing a breathable film comprising uniaxially stretching a film 
made of a resin composition comprising (1) 100 parts by weight of a linear 
low-density polyethylene resin having a density of from 0.870 to 0.915 
g/cm.sup.3 and containing from 15 to 50% by weight of a component which is 
extractable with xylene at room temperature and which has a weight average 
molecular chain length of from 1,000 to 9,000 .ANG.; (2) from 50 to 400 
parts by weight of a filler; and (3) from 0.5 to 8 parts by weight of a 
nonionic surface active agent at a temperature of from 30.degree. to 
80.degree. C. at a stretch ratio of from 1.2 to 8 in the mechanical 
direction, or biaxially stretching said film at a temperature of from 
40.degree. to 100.degree. C. at a stretch ratio of from 1.1 to 8.0 in the 
mechanical direction and then at a temperature of from 70.degree. to 
100.degree. C. at a stretch ratio of not higher than 6.0 in the 
transverse direction. 
DETAILED DESCRIPTION OF THE INVENTION 
The term "room temperature" as referred to herein for measurement of the 
xylene content means a temperature of 25.+-.1.degree. C. 
The term "excellent film moldability" as referred to herein means that 
light-gage films having a uniform thickness can be molded with neither 
film fracture nor formation of pinholes and at a high rate of molding; and 
the term "excellent film stretchability as referred to herein means that 
films can be stretched into light-gage films having a uniform thickness 
with neither unevenness in stretching nor film fracture. 
The linear low-density polyethylene resin which is used in the present 
invention is one having a density of from 0.870 to 0.915 g/cm.sup.3 and 
containing from 15 to 50% by weight, preferably from 20 to 30% by weight, 
of a component which is extractable with xylene at room temperature (this 
component being hereinafter referred to as "CXS component") and which has 
a weight average molecular chain length of from 1,000 to 9000 .ANG.. If 
the weight average molecular chain length of the CXS component is less 
than 1,000 .ANG., the film moldability is reduced, and the film surface 
becomes sticky. On the other hand, if it is in excess of 9,000 .ANG. since 
it becomes difficult to increase the proportion of the filler to be 
compounded in the resin composition, a breathable film having high 
breathability cannot be obtained. On the other hand, if it is in excess of 
50% by weight, a film having a uniform thickness cannot be obtained. If 
the density is less than 0.870 g/cm.sup.3, the film surface becomes 
sticky, and the strength and heat resistance of the film are reduced. On 
the other hand, if it is in excess of 0.915 g/cm.sup.3, since the 
proportion of the filler to be compounded in the resin composition cannot 
be increased, a breathable film having high breathability cannot be 
obtained. The linear low-density polyethylene resin which is used in the 
present invention can be produced by known methods as described, for 
example, in Japanese Patent Application (OPI) Nos. 99209/81 and 230011/84. 
Examples of the filler which can be used in the present invention include 
inorganic fillers such as carbonates (such as calcium carbonate, magnesium 
carbonate, and barium carbonate), sulfates (such as barium sulfate, 
magnesium sulfate, and calcium sulfate), phosphates (such as magnesium 
phosphate and calcium phosphate), hydroxides (such as magnesium hydroxide 
and aluminum hydroxide), oxides (such as alumina, silica, magnesium oxide, 
calcium oxide, zinc oxide, and titanium oxide), chlorides (such as zinc 
chloride and iron chloride), metal powders (such as aluminum powder, iron 
powder, and copper powder), mica, glass powder, zeolite, activated clay, 
diatomaceous earth, talc, carbon black, and volcanic ash; and organic 
fillers such as cellulose powders (such as wood powder and pulp powder) 
and synthetic powders (such as nylon powder, polyester powder, 
polycarbonate powder, polypropylene powder, and poly(4-methylpentene-1) 
powder). These compounds can be used alone or in combination with each 
other. From the viewpoints of breathability and touch and appearance of 
films, calcium carbonate, barium sulfate, and talc are particularly 
preferred. The average particle diameter of the filler is preferably from 
0.1 to 20 .mu.m and particularly preferably from 0.8 to 5.0 .mu.m from the 
viewpoints of uniform film stretchability and touch and appearance. The 
amount of the filler to be compounded is from 50 to 400 parts by weight, 
preferably from 60 to 200 parts by weight, based on 100 parts by weight of 
the linear low-density polyethylene resin. If the amount of the filler is 
less than 50 parts by weight, the breathability is insufficient. On the 
other hand, if it is in excess of 400 parts by weight, the film 
moldability is reduced and, thus, not only films of uniform thickness 
cannot be obtained but also the strength of the film is low. 
In the present invention, in order to increase the uniform dispersibility 
of the filler when the amount of the filler compounded is increased and 
further to maintain the excellent stretchability, a nonionic surface 
active agent is used. Examples of the nonionic surface active agent 
include glycerine esters and sorbitan esters of fatty acids having from 12 
to 22 carbon atoms. It is particularly preferred that monoglycerine 
monostearate or diglycerine distearate is used alone or as a mixture 
thereof: The amount of the nonionic surface active agent to be compounded 
is from 0.5 to 8 parts by weight, preferably from 0.5 to 2 parts by 
weight, based on 100 parts by weight of the linear low-density 
polyethylene resin. If the amount of the nonionic surface active agent is 
less than 0.5 part by weight, the uniform dispersibility of the filler is 
low. On the other hand, if it is in excess of 8 parts by weight, problems 
such as bleeding out of the nonionic surface active agent contained in the 
film to the surface of the film arise. 
The breathable film of the present invention can be produced as follows. 
In the first place, a linear low-density polyethylene, a filler, and if 
desired, a nonionic surface active agent are mixed or kneaded by the usual 
procedures using a roll type or Banbury type kneader or extruder to form a 
resin composition. This resin composition is then molded into a film by 
usual film forming techniques such as inflation molding, calender molding, 
or T-die molding. Thereafter, the film is stretched either uniaxially or 
biaxially to impart breathability thereto. 
In the case of uniaxial stretching, roll stretching is usually preferred. 
Stretching techniques such as tubular stretching in which the stretching 
direction is emphasized can be employed as well. This stretching can be 
performed by one-step process or two or more-step process. The stretch 
ratio is from 1.2 to 8, preferably from 1.6 to 2.5. If the stretch ratio 
is less than 1.2, the breathability is very low and the touch and 
appearance are poor. On the other hand, if it is in excess of 8, films of 
uniform thickness are difficult to obtain and, moreover, the resulting 
breathable film likely causes heat shrinkage. The temperature at which the 
stretching is performed is an important factor exerting influences on the 
breathability and touch and appearance of the breathable film obtained. In 
general, if the stretching is performed at high temperatures, the tough 
and appearance are good but the breathability is not high, while on the 
other hand, if the stretching is performed at low temperatures, the 
breathability is high but the touch and appearance are not good. The 
breathable film of the present invention as obtained by stretching at low 
temperatures, however, has high breathability and good touch and 
appearance at the same time. The temperature at which the stretching is 
performed in accordance with the present invention is preferably from 30 
to 80.degree. C. and more preferably from 40.degree. to 60.degree. C. from 
the viewpoints of breathability and tough and appearance. 
In the case of biaxial stretching, the film is first stretched in the 
mechanical direction at a temperature of from 40.degree. to 100.degree. C. 
at a stretch ratio of from 1.1 to 8.0 and then in the transverse direction 
at a temperature of from 70.degree. to 100.degree. C. at a stretch ratio 
of not higher than 6. In the stretching in the mechanical direction, if 
the temperature is lower than 40.degree. C., the film shrinks just after 
the stretching and, thus, no uniform film can be obtained. On the other 
hand, if the temperature is in excess of 100.degree. C., high 
breathability cannot be obtained. If the stretch ratio is less than 1.1, 
high breathability is difficult to obtain, whereas if it is in excess of 
8.0, the film strength balance cannot be obtained even by the subsequent 
stretching in the transverse direction. The subsequent stretching in the 
transverse direction is carried out for the purposes of greatly increasing 
the film breathability and at the same time, of maintaining the film 
strength balance. With regard to this stretching in the transverse 
direction, it is not preferred from the viewpoint of molding stability 
that the temperature is outside the range of from 70 to 100.degree. C. and 
the stetch ratio is more than 6.0. In order to obtain films of high 
breathability at a low stretch ratio, it is more preferred for the biaxial 
stretching to be carried out by first stretching in the mechanical 
direction at a temperature of from 50.degree. to 85.degree. C. at a 
stretch ratio of from 1.2 to 4.0 and then stretching in the transverse 
direction at a temperature of from 80.degree. to 95.degree. C. at a 
stretch ratio of not higher than 3.0. The reason why the breathability is 
greatly increased by biaxial stretching is considered to be caused by the 
fact that microvoids formed by stretching in the mechanical direction at 
low temperatures are extended and deformed into a circular form by the 
subsequent stretching in the transverse direction because in the 
stretching in the transverse direction, they are exposed to high 
temperatures in the state that a tensile stress is applied. Further, the 
reason why the strength balance of the film is maintained is considered to 
be caused by the fact that the form of the microvoids and the state of 
orientation of the resin are changed. Accordingly, in the biaxial 
stretching, it is preferred that the stretchings in the mechanical and 
transverse directions are carried out successively under different 
stretching conditions; if the biaxial stretching is carried out at the 
same time, no satisfactory breathable films can be obtained. The 
stretching in the mechanical direction is preferably carried out by means 
of rolls and can be carried out by one-step process or two or more-step 
process. The stretching in the transverse direction is preferably carried 
out in hot air. 
In order to more increase the breathability and to relieve the heat 
shrinkability, the film obtained by stretching as described above is 
preferably subjected to a subsequent heat setting treatment. The lower 
temperature limit in the heat setting treatment is 60.degree. C., and the 
upper temperature limit is a temperature of 5.degree. C. lower than Tm 
(the maximum peak temperature (.degree. C.) of the linear low-density 
polyethylene as determined by the use of a differential scanning 
calorimeter). It is not preferred to apply the heat setting treatment for 
a period of time more than necessary because the breathability is reduced. 
Preferred conditions for the heat setting treatment are such that the 
temperature is about 10.degree. C. lower than Tm and the period of time is 
from 0.3 to 30 seconds. 
To the resin composition from which the breathable film of the present 
invention is obtained, antioxidants and antiblocking agents can be 
compounded within such ranges that the effects of the present invention 
are not substantially impaired. 
In accordance with the present invention, breathable films having excellent 
film moldability and film stretchability and further showing high 
breathability, good touch and appearance, and high strength can be 
obtained by using a resin composition containing a specified polyethylene 
resin as a resin component. 
As set forth in the Examples and Comparative Examples as described 
hereinafter, if polyethylene resins other than the specified polyethylene 
resin of the present invention are used or other construction requirements 
of the present invention are not met, breathable films of the present 
invention cannot be obtained. 
In accordance with the present invention, desired breathable films can be 
obtained efficiently. When a specified polyethylene resin of the present 
invention is used, biaxial stretching which has been considered to be 
difficult to apply when the usual polyethylene resins are used can be 
applied and, thus, high breathability can be attained by applying 
stretching at low stretch ratios. 
The breathable film obtained by the present invention can be used in 
various applications for, e.g., leisure wear, sportswear, tent, mesh, 
clothings, wall paper, wrapping materials, packagings for medical and 
health care products, disposable diapers, feminine hygiene products, 
rainwear, medical treatment, drapes, gowns, sterile wraps, bandages, wound 
dressings, herbicide release, etc. 
The present invention is described below in greater detail with reference 
to the following examples. 
Methods of measuring the physical properties shown in the Examples and 
Comparative Examples are as follows. 
Weight Average Molecular Chain Length 
The weight average molecular chain length of the CXS component was measured 
by the use of a gel permeation chromatograph (GPC) Model 811 (produced by 
Toyo Soda Manufacturing Co., Ltd.) provided with two columns of GMH6-HD at 
a temperature of 130.degree. C., with polystyrene being taken as a 
standard. 
Density 
The density of the resin was measured at 23.degree. C. by the density 
gradient tube method according to JIS K6760-1981. 
Breathability 
The breathability of the film was determined by measuring the amount of air 
which passed through the film during the time of 1 minute when an air 
pressure of 0.2 kg/cm.sup.2 was applied at room temperature. 
Shrinkage Ratio 
The heat shrinkability of the breathable film was indicated in terms of a 
ratio (percent) of shrinked length of the film when it was treated at 
80.degree. C. for 60 minutes to the original length of the film. This 
measurement was conducted in both the mechanical direction (hereinafter 
referred to as "MD") and the transverse direction (hereinafter referred to 
as "TD"). 
Tear Strength 
The Elmendorf tear strength of the breathable film was measured according 
to JIS P8116 in both MD and TD. 
Touch and Appearance 
The touch and appearance of the breathable film were determined by touching 
with a hand and observing by eyes. The rating were as follows: 
.circleincircle.: touch and no unevenness in stretching observed. 
.circle.: Good touch but some unevenness in stretching observed. 
.DELTA.: Somewhat stiff touch and some unevenness in stretching observed. 
.times.: Considerably stiff touch and serious unevenness in stretching 
observed. 
Melt Flow Rate 
The melt flow rate of the resin (hereinafter referred to as "MFR") was 
measured according to JIS K6760. 
Tensile Strength 
The tensile strength at breakage was measured according to JIS Z1702 in 
both MD and TD.

EXAMPLE 1 
100 parts by weight of linear low-density polyethylene containing 25% by 
weight of a CXS component having a weight average molecular chain length 
of 6,000 .ANG. and having a density of 0.9003 g/cm.sup.3 and an MFR of 
1.9, 170 parts by weight of calcium carbonate having an average particle 
diameter of 1.25 .mu.m, and 3.3 parts by weight of monoglycerine 
monostearate were previously mixed in a tumbling mixer Model MT50 
(manufactured by Morita Seiki Co., Ltd.) and then kneaded at from 
120.degree. to 150.degree. C. for 5 minutes by the use of a Banbury mixer 
Model BR (manufactured by Kobe Seiko Co., Ltd.). The resin composition 
thus obtained was subjected to inflation molding by the use of a 50 
mm.phi. extruder Model EA-50 (die diameter 100 mm.phi.; spiral die; 
manufactured by Modern Machinery Co., Ltd.) to produce a 120 .mu.m-thick 
film. Conditions for the extrusion molding were such that the cylinder 
temperature was 170.degree. C. in the vicinity of the bottom of hopper, 
170.degree. C. in the central portion, and 190.degree. C. in the vicinity 
of the head, respectively; the head and die temperatures were respectively 
190.degree. C.; and the blow ratio was about 2.0. This film was uniaxilly 
stretched in MD at a temperature of 65.degree. C. at a stretch ratio of 4 
by the use of a roll stretching machine (manufactured by Nippon Seiko Co., 
Ltd.) to produce a breathable film having a thickness of about 35 .mu.m. 
The results are shown in Table 1. The breathability and touch and 
appearance of the film were good. 
EXAMPLE 2 
A breathable film was produced in the same manner as in Example 1 except 
that 210 parts by weight of barium sulfate having an average particle 
diameter of 0.6 .mu.m as a filler and 5.0 parts by weight of diglycerine 
distearate as a nonionic surface active agent were used. The results are 
shown in Table 1. The breathability and touch and appearance of the 
resulting breathable film were good. 
EXAMPLE 3 
The breathable film obtained in Example 1 was subjected to heat setting at 
95.degree. C. for 6 seconds. The results are shown in Table 1. The 
breathability was greatly increased as compared with in Example 1 and, 
furthermore, the shrinkage ratio was small. 
EXAMPLE 4 
A breathable film was produced in the same manner as in Example 1 except 
that the nonionic surface active agent was not used. The results are shown 
in Table 1. The breathability and touch and appearance of the film were 
good. 
EXAMPLE 5 
A breathable film was produced in the same manner as in Example 1 except 
that 200 parts by weight of MS talc (produced by Nippon Talc Co., Ltd.) as 
a filler was used and no nonionic surface active agent was used. The 
breathability and touch and appearance of the breathable film were good. 
COMATIVE EXAMPLE 1 
A film having a thickness of about 35 .mu.m was produced by stretching a 
120 .mu.m-thick film in the same manner as in Example 1 except that the 
proportion of the calcium carbonate to be compounded was changed to 43 
parts by weight. The results are shown in Table 1. As compared with 
Example 1, the stretched film had no breathability at all, and its 
shrinkage ratio was very large. 
COMATIVE EXAMPLE 2 
A breathable film was produced in the same manner as in Example 4 except 
that as the polyethylene resin, linear low-density polyethylene having 5% 
by weight of the CXS component, a density of 0.925 g/cm.sup.3, and an MFR 
of 1.5 was used. The results are shown in Table 1. Heat shrinkability of 
the film was good, but as compared with Example 4, the touch and 
appearance of the film were very bad. 
COMATIVE EXAMPLE 3 
A breathable film was produced in the same manner as in Example 4 except 
that the film was uniaxially stretched in MD at a temperature of 
113.degree. C. at a stretch ratio of 1.5 by the use of rolls. The results 
are shown in Table 1. As compared with Example 4, the breathable film had 
almost no breathability, and its touch and appearance were not good. 
COMATIVE EXAMPLE 4 
A resin composition was produced in the same manner as in Example 1 except 
that the amount of the calcium carbonate to be compounded was changed to 
153 parts by weight. This resin composition was molded into a 60 
.mu.m-thick film by the same inflation molding method as in Example 1, and 
the film thus obtained was uniaxially stretched in MD at a temperature of 
65.degree. C. at a stretch ratio of 1.5 by the use of rolls to produce a 
breathable film having a thickness of about 40 .mu.m. The results are 
shown in Table 1. As compared with Example 1, the stretched film had no 
breathability, and its touch and appearance were not good. 
COMATIVE EXAMPLE 5 
A resin composition was prepared in the same manner as in Example 1 except 
that the amount of the calcium carbonate to be compounded was changed to 
450 parts by weight. While it was attempted to make a film from this resin 
composition, no film was obtained because the amount of the filler used 
was too large. 
EXAMPLE 6 
A 60 .mu.m-thick film obtained by inflation molding in the same manner as 
in Example 1 was stretched in MD at a temperature of 65.degree. C. at a 
stretch ratio of 5.0 to produce a breathable film having a thickness of 22 
.mu.m. The results are shown in Table 1. 
EXAMPLE 7 
A 60 .mu.m-thick film was obtained by inflation molding in the same manner 
as in Example 1 was uniaxially stretched in MD at a temperature of 
65.degree. C. at a stretch ratio of 1.5 by the use of rolls and, then, in 
TD at a temperature of 90.degree. C. in hot air at a stretch ratio of 1.5 
to produce a breathable film. The results are shown in Table 1. The 
breathability and touch and appearance of the film were good, and the film 
had a balanced strength. 
EXAMPLES 8 TO 11 
Breathable films were produced in the same manner as in Example 7 except 
that the stretch ratio and temperature in the stretching in MD and TD were 
changed as shown in Table 1. The results are shown in Table 1. The 
breathability and touch and appearance of the film were good, and the film 
had a balanced strength. 
EXAMPLES 12 AND 13 
Breathable films were produced in the same manner as in Example 7 except 
that the amount of the nonionic surface active agent used was changed as 
shown in Table 1. The results are shown in Table 1. The breathability and 
touch and appearance of the film were good, and the film had a balanced 
strength. 
COMATIVE EXAMPLE 6 
A 120 .mu.m-thick film was produced by inflation molding in the same manner 
as in Example 7 except that the amount of the calcium carbonate to be 
compounded was changed to 43 parts by weight. The film was uniaxially 
stretched in MD at a temperature of 75.degree. C. at a stretch ratio of 4 
by the use of rolls and, then, in TD at a temperature of 90.degree. C. in 
hot air at a stretch ratio of 1.25 to produce a stretched film having a 
thickness of about 35 .mu.m. The results are shown in Table 1. This film 
did not have breathability at all. 
COMATIVE EXAMPLE 7 
While it was attempted to stretch a 60 .mu.m-thick film obtained by 
inflation molding as in Example 7 in MD at a temperature of 65.degree. C. 
at a stretch ratio of 1.5 and, then, in TD at a temperature of 105.degree. 
C. at a stretch ratio of 1.25, film cutting occurred and, hence, a 
breathable film could not be obtained. 
COMATIVE EXAMPLE 8 
A 60 .mu.m-thick film was produced by inflation molding in the same manner 
as in Example 7 except that as the polyethylene resin, a high-pressure 
polyethylene resin having a density of 0.925 g/cm.sup.3 and an MFR of 1.5 
was used. While it was attempted to stretch this film in MD at a 
temperature of 95.degree. C. at a stretch ratio of 1.5 and, then, in TD at 
a temperature of 110.degree. C. at a stretch ratio of 1.25, film cutting 
occurred and, hence, a breathable film could not be obtained. 
COMATIVE EXAMPLE 9 
A breathable film was produced in the same manner as in Example 7 except 
that 9.0 parts by weight of monoglycerine monostearate as the nonionic 
surface active agent was used. The results are shown in Table 1. The 
breathable film obtained had high breathability and balanced strength. 
However, the monoglycerine monostearate bleeded out to the surface of the 
film, and the film had no value as a commercial product. 
TABLE 1 
__________________________________________________________________________ 
Nonionic 
Polyethylene Surface Stretching 
Stretching 
Example 
Resin Filler Active Agent 
Film 
in MD in TD 
or Com- Parts Parts Parts 
Thick- 
Tem- Tem- 
parative by by by ness 
perature perature 
Example 
Type.sup.(1) 
weight 
Type weight 
Type.sup.(2) 
weight 
(.mu.m) 
(.degree.C.) 
Ratio 
(.degree.C.) 
Ratio 
__________________________________________________________________________ 
Example 1 
A 100 CaCO.sub.3 
170 M 3.3 120 65 4 -- -- 
Example 2 
A 100 BaCO.sub.4 
210 D 5.0 120 65 4 -- -- 
Example 3.sup.(3) 
A 100 CaCO.sub.3 
170 M 3.3 120 65 4 -- -- 
Example 4 
A 100 CaCO.sub.3 
170 -- -- 120 65 4 -- -- 
Example 5 
A 100 MS talc 
200 -- -- 120 65 4 -- -- 
Comparative 
A 100 CaCO.sub.3 
43 M 3.3 120 65 4 -- -- 
Example 1 
Comparative 
B 100 CaCO.sub.3 
170 -- -- -- 65 4 -- -- 
Example 2 
Comparative 
A 100 CaCO.sub.3 
170 -- -- 120 113 1.5 -- -- 
Example 3 
Comparative 
A 100 CaCO.sub.3 
153 M 3.3 60 65 1.5 -- -- 
Example 4 
Comparative 
A 100 CaCO.sub.3 
450 M 3.3 Molding was not possible. 
Example 5 
Example 6 
A 100 CaCO.sub.3 
170 M 3.3 60 65 5.0 -- -- 
Example 7 
A 100 CaCO.sub.3 
170 M 3.3 60 65 1.5 90 1.5 
Example 8 
A 100 CaCO.sub.3 
170 M 3.3 60 65 2.0 90 1.5 
Example 9 
A 100 CaCO.sub.3 
170 M 3.3 60 65 2.0 90 1.25 
Example 10 
A 100 CaCO.sub.3 
170 M 3.3 60 65 3.5 93 1.20 
Example 11 
A 100 CaCO.sub.3 
170 M 3.3 60 65 3.0 85 1.5 
Example 12 
A 100 CaCO.sub.3 
170 M 0.8 60 65 1.5 90 1.5 
Example 13 
A 100 CaCO.sub.3 
170 M 6.5 60 65 1.5 90 1.5 
Comparative 
A 100 CaCO.sub.3 
43 M 3.3 120 75 4 90 1.25 
Example 6 
Comparative 
A 100 CaCO.sub.3 
170 M 3.3 60 65 1.5 105 1.25 
Example 7 
Comparative 
B 100 CaCO.sub.3 
170 M 3.3 60 95 1.5 110 1.25 
Example 8 
Comparative 
A 100 CaCO.sub.3 
170 M 9.0 60 65 1.5 90 1.5 
Example 9 
__________________________________________________________________________ 
Thickness of Tear 
Example of 
Breathable 
Degree of 
Strength 
Tensile Shrinkage 
Comparative 
Film Breathability 
(kg/cm.sup.2) 
Strength 
Ratio (%) 
Touch and 
Example 
(.mu.m) (cc/min) 
MD TD MD TD MD TD Appearance 
__________________________________________________________________________ 
Example 1 
about 35 
210 20 200 -- -- 53 0 .circleincircle. 
Example 2 
about 35 
180 25 210 -- -- 42 -1 .circleincircle. 
Example 3.sup.(3) 
about 35 
400 9 110 -- -- 10 1 .circleincircle. 
Example 4 
about 35 
224 17 189 -- -- 48 -1 .circle. 
Example 5 
about 35 
245 15 177 -- -- 44 -1 .circle. 
Comparative 
about 35 
0 260 630 -- -- 70 -14 .circle. .about..DELTA. 
Example 1 
Comparative 
-- 513 8 101 -- -- 17 -2 X 
Example 2 
Comparative 
about 35 
2 89 293 -- -- 6 -1 X 
Example 3 
Comparative 
40 0 -- -- -- -- X 
Example 4 
Comparative -- 
Example 5 
Example 6 
22 262 5 143 240 29 64 -3 .circle. 
Example 7 
-- 480 61 120 105 85 6 8 .circle. 
Example 8 
-- 1220 29 58 112 76 9 8 .circleincircle. 
Example 9 
-- 270 102 163 158 90 9 6 .circle. 
Example 10 
-- 316 27 86 102 23 11 5 .circle. 
Example 11 
-- 1880 18 26 147 71 10 8 .circleincircle. 
Example 12 
-- 570 56 114 102 80 6 5 .circle. 
Example 13 
-- 450 63 121 111 93 10 8 .circle. 
Comparative 
about 35 
0 -- -- -- -- -- -- .DELTA. 
Example 6 
Comparative 
Film cutting occurred. 
Example 7 
Comparative 
Film cutting occurred. 
Example 8 
Comparative 
-- 461 62 119 115 90 9 7 X 
Example 9 
__________________________________________________________________________ 
[Note] 
(1): 
Weight Average 
Content 
Molecular Chain 
of CXS 
Length Component 
Density 
Type 
(.ANG.) (wt %) 
(g/cm.sup.3) 
MFR 
A 6,000 25 0.9003 
1.9 
B -- 5 0.925 
1.5 
(2): 
M: monoglycerine monostearate 
D: diglycerine distearate 
(3): 
The breathable film of the Example 1 
was subjected to heat setting. 
While the invention has been described in detail and with reference to 
specific embodiments thereof, it will be apparent to one skilled in the 
art that various changes and modifications can be made therein without 
departing from the spirit and scope thereof.