Back to EveryPatent.com
| United States Patent |
5,109,050
|
|
Takahashi
, et al.
|
April 28, 1992
|
Thermoplastic polyurethane resin
Abstract
Disclosed is a thermoplastic polyurethane resin composition which contains
a thermoplastic polyurethane resin (A) and a modified polyolefin resin (B)
as its components. The polyurethane resin shows excellent flexibility,
smooth touch, and stretching property when molded in the form of films or
sheets. It is quite suitable for excretion-treating materials such as a
diaper.
| Inventors:
|
Takahashi; Hoyo (Izumiotsu, JP);
Hirose; Takuji (Sennan, JP);
Ishihara; Kunitoshi (Izumiotsu, JP)
|
| Assignee:
|
Dainippon Ink and Chemicals, Inc. (Tokyo, JP)
|
| Appl. No.:
|
429431 |
| Filed:
|
October 31, 1989 |
Foreign Application Priority Data
| Oct 31, 1988[JP] | 63-273151 |
| Intern'l Class: |
C08K 007/14 |
| Field of Search: |
525/66,131,130
524/425,427,507
|
References Cited
U.S. Patent Documents
| 3969313 | Jul., 1976 | Aishima et al. | 524/427.
|
| 3970716 | Jul., 1976 | Evers et al. | 524/507.
|
| 4089911 | May., 1978 | Itoh et al. | 524/507.
|
| 4151153 | Apr., 1979 | Ashcroft et al. | 524/425.
|
| 4206102 | Jun., 1980 | Britain et al. | 524/507.
|
| 4318959 | Mar., 1982 | Evans et al. | 428/364.
|
| 4412025 | Oct., 1983 | Corwin et al. | 524/241.
|
| 4423185 | Dec., 1983 | Matsumoto et al. | 525/66.
|
| 4735985 | Apr., 1988 | Oien | 524/315.
|
| 4883837 | Nov., 1989 | Zabrocki | 525/66.
|
Primary Examiner: Morgan; Kriellion S.
Assistant Examiner: Cain; Edward J.
Attorney, Agent or Firm: Armstrong, Nikaido, Marmelstein, Kubovcik & Murray
Claims
We claim:
1. A thermoplastic polyurethane resin composition comprising from 80 to 99
parts by weight of a thermoplastic polyurethane resin (A), and from 1 to
20 parts by weight of a modified polyolefin resin (B).
2. The thermoplastic polyurethane resin composition as claimed in claim 1,
wherein said thermoplastic polyurethane resin (A) has its properties which
are Shore A hardness of from 80 to 100, tensile strength of 200
kg/cm.sup.2 or more, and fracture elongation of 300% or more.
3. The thermoplastic polyurethane resin composition as claimed in claim 1,
wherein said modified polyolefin resin (B) contains an olefin copolymer
comprising carboxyl and/or epoxy groups.
4. The thermoplastic polyurethane resin composition as claimed in claim 1,
wherein said modified polyolefin resin (B) contains a modified
ethylene-propylene copolymer.
5. The thermoplastic polyurethane resin composition as claimed in claim 1,
wherein said resin contains a filler.
6. Thermoplastic polyurethane resin composition as claimed in claim 5,
wherein said filler is calcium carbonate.
7. The thermoplastic polyurethane resin composition as claimed in claim 1,
wherein said resin is in the form of films or sheets.
8. An excretion-treating material comprising the thermoplastic polyurethane
resin composition in the form of films or sheets as claimed in claim 7.
9. The excretion-treating material as claimed in claim 8, wherein said
excretion treating material is a diaper.
Description
BACKGROUND OF THE INVENTION
This invention relates to a thermoplastic polyurethane resin composition,
especially to an elastic polyurethane resin composition which gives
excellent smooth touch when used in the form of a film or sheet.
The elastic films, which have been so far applied to an excretion-treating
material such as a paper diaper, have usually been composed of single
resin of SBR (styrene-butadiene rubber), the mixed resin of SBR and
thermoplastic polyurethane resin, or single resin of thermoplastic
polyurethane. In addition to those resins, acid amide-type lubricants are
blended in order to prevent a tacky adhesion.
However, those films almost lack pliability (high low-modulus), and
stretching properly. Especially, when applied to the paper diaper for the
children, the body is strongly bound with those films. Accordingly,
various means such as changing the construction of film blades or films
are made to cover up the above-cited defects. Therefore, it has been
desired to obtain fully satisfactory elastic films especially applied to
the excretion-treating materials.
SUMMARY OF THE INVENTION
The primary object of the present invention is to provide a thermoplastic
polyurethane resin composition having flexibility and low tackiness when
molded or rolled.
Another object of the present invention is to provide a thermoplastic
polyurethane resin composition suitable for practical use, for example, in
excretion-treating materials such as a paper diaper.
The above objects are accomplished by the following composition;
thermoplastic polyurethane resin composition comprising a thermoplastic
polyurethane resin (A), and a modified polyolefin resin (B) as its
components.
DETAILED DESCRIPTION OF THE INVENTION
The above-cited component which is the thermoplastic polyurethane resins
applied to this invention preferably has a hardness (Shore A ) of from 80
to 100.degree., more preferably from 85 to 95.degree. at 25.degree. C., a
tensile strength of 200 kg/cm.sup.2 or more, more preferably from 300 to
500 kg/cm.sup.2, and fracture elongation of 300% or more, more preferably
400% or more.
The thermoplastic polyurethane resin which can be used in this invention is
preferably a reaction product of a polyhydroxyl compound (polyol
component) and a polyisocyanate compound (isocyanate component).
Polyhydroxyl compounds are, for example, various polyester polyols and/or
polyether polyols which are generally used for the preparation of urethane
compounds.
Polyester polyols described herein are the condensation products of
polyvalent alcohol and polybasic carboxylic acid, hydroxycarboxylic acid
and polyhydric alcohol, poly-hydric alcohols used herein are, for example,
ethylene glycol, propylene glycol, butanediol, diethylene glycol,
glycerol, hexanetriol, trimethylolpropane.
Polybasic carboxylic acids used herein are, for example, adipic acid,
glutaric acid, azelaic acid, fumaric acid, maleic acid, phthalic acid,
terephthalic acid, dimeric acid, pyromellitic acid.
Condensation products of a hydroxycarboxylic acid and a polyvalent alcohol
are, for example, castor oil, reaction products of castor oil and ethylene
glycol, or castor oil and propylene glycol.
Moreover, polyesterpolyols which are obtained by the ring-opening
polymerization of various lactones such as .epsilon.-caprolactone are
preferably used in this invention.
These `lactone-type` polyester polyols can be also used in this invention
which addition-polymerize a polyhydric alcohol and one or more lactones
such as .epsilon.-caprolactone, .delta.-valerolactone, and
.beta.-methyl-.delta.-valerolactone.
Polyether polyols used in this invention are, for example, addition
polymerization products of one or more compounds such as ethylene oxide,
propylene oxide, alkylene oxide butylene oxide, and tetrahydrofuran, and
compounds having two or more active hydrogen atoms, which are generally
used for the preparation of well-known polyurethane resins.
The above-cited compounds having two or more active hydrogen atoms are, for
example, polyvalent alcohols, polybasic carboxylic acid, amines such as
ethylenediamine, hexamethylenediamine, alkanolamines such as ethanolamine,
propanolamine, polyvalent phenols such as resorcin, bisphenol, and castor
oil.
Polyhydroxyl compounds used in this invention are one or more polyester
polyols or polyether polyols.
Moreover, low molecular polyhydroxy compounds such as polyvalent alcohols
described above can also be used as chain-extending agents together with
above-cited polyester polyols and polyether polyols.
Polyisocyanate compounds used in this invention are those compounds which
have two or more isocyanate groups per molecule, and in general are also
used for the preparation of well-known type polyurethane resins. These
are, for example, aromatic polyisocyanate compounds such as tolylene
diisocyanate, diphenylmethane diisocyanate, dianisidyne diisocyanate,
naphthalene diisocyanate, triphenylmethane triisocyanate,
bis(diisocyanatotolyl)phenylmethane, polymethylene polyphenyl
polyisocyanate, aliphatic or alicyclic polyisocyanate compounds such as
isophorone diisocyanate, dicyclohexylmethane diisocyanate (hydrogenated
diphenylmethane diisocyanate), hexamethylene diisocyanate, xylylene
diisocyanate, hydrogenated tolylene diisocyanate, isopropylidene
bis(cyclohexyl isocyanate).
In the present invention, two or more kinds of the polyisocyanate compounds
can be used.
Especially, it is preferable to use aliphatic or alicyclic polyisocyanates
together with aromatic polyisocyanate compounds.
As the polyol components of the polyurethane resin, all the polyhydroxy
compounds described above can be used which are applied to the preparation
of urethane polymer containing isocyanate groups That is to say, one or
more kinds of polyester polyols or polyether-polyols described above can
be used Moreover, low molecular polyhydroxy compounds such as the
above-cited polyvalent alcohols are also used together.
The component which is the modified polyolefin resins (B) applied to this
invention includes those polyolefin resins which are modified by acids or
epoxy compounds.
They are preferably olefin copolymers containing carboxyl group and/or
olefin copolymers containing epoxy group.
The above-cited component (B) is preferably used in amounts of from 1 to 50
parts by weight. On the other hand, component (A) is used in amounts of
from 99 to 50 parts by weight in the composition of the thermoplastic
polyurethane resin obtained in this invention. More preferably, (A)/(B) in
weight ratio is (98 to 60)/(2 to 40).
The olefin copolymer containing carboxyl group should comprise 1-olefin,
for example, ethylene, propylene, butane-1, isobutene, pentene-1,
hexene-1, decene-1,4-methylbutene-1,4-methylpentene-1,
4,4-dimethylpentene-1, vinylcyclo-hexane, styrene, .alpha.-methylstyrene,
styrene substituted by a secondary alkyl group or its similar compound, in
amounts of at least 50 mole %, preferably at least 70 mole %.
The mixture of these two or more compounds can also be used.
Among these compounds, a copolymer of ethylene and butene 1 or propylene is
most preferred Examples of its commercially available products include a
series of `TAFMER A` (ethylene-butene-1 copolymer, manufactured by Mitsui
Petrochemical Industries, Ltd.) such as `TAFMER-A4085`, `TAFMER A4090,
TAFMER-A20090`, and a series of `TAFMER-P` (ethylene propylene copolymer,
manufactured by Mitsui Petrochemical Industries, Ltd.) such as `TAFMER
P-0280`, `TAFMER P0480`, `TAFMER-P0680`, `TAFMER P0880`.
Olefin copolymers containing carboxyl group described above are prepared by
the methods of polymerization, such as the direct copolymerization of
.alpha., .beta.-unsaturated carboxylic acid comonomers and the above-cited
olefins, the graft copolymerization of the above cited comonomers grafted
onto polyolefins, or polyolefin copolymers, and so on.
As the acid components used herein, many acids are available. Examples
thereof include acrylic acid, methacrylic acid, itaconic acid, maleic acid
(anhydride), fumaric acid, and monoesters of the above-cited carboxylic
acids. Among these compounds, acrylic acid, methacrylic acid, and maleic
acid (anhydride) are preferably used. More preferably, maleic acid
(anhydride) is used, because of its sufficient acid-modification effect,
even if small amounts of them are added in comparison with the amounts of
others.
As the preferable olefin copolymers containing carboxyl group, there are
cited, for example, ethylenebutene-1-maleic acid (anhydride) copolymer,
ethylenepropylene-maleic acid (anhydride) copolymer.
Olefin copolymers containing epoxy group are prepared by the methods such
as direct copolymerization of glycidyl esters of
.alpha.,.beta.-unsaturated carboxylic acids as epoxy compounds are the
above-cited olefins, graft copolymerization of the above cited esters
grafted onto polyolefin or polyolefin copolymers.
Glycidyl esters used herein have the general formula shown below:
##STR1##
In the above formula, R represents a hydrogen atom, or a lower alkyl group.
The above-cited esters or mixtures of two or more kinds of esters can be
used in this invention. For example, glycidyl acrylate, glycidyl
methacrylate, glycidyl ethacrylate. Among these esters, glycidyl
methacrylate is preferably used.
Such polyolefin resins modified by the carboxyl and/or epoxy groups contain
monomers having the above-cited functional groups in an amounts of from
0.01 to 20 weight %, preferably from 0.05 to 5 weight % as these
components.
The small amounts of various kinds of agents can be added to the
thermoplastic polyurethane resin obtained in this invention, for example,
mold releasing agents, coupling agents, coloring agents, lubricant,
weather stabilizers, foaming agents, rust preventives, emulsifier, mold
preventives, fillers. Especially, in this invention, it is important in
view of preventing tackiness to add the fillers. As fillers used here,
there are, for example, calcium carbonate, clay, alumina powder, natural
silica powder, talc, barium sulfate, silica powder, mica, glass powder.
Among these fillers, calcium carbonate is preferably used.
The thermoplastic polyurethane resin obtained in this invention has a good
flexibility, and gives smooth touch. Therefore, it can be applied in the
form of films, sheets, or moldings, preferably films or sheets to the
things which are brought in contact with the skin of a human body.
Especially, it is available for stretching films which often come into
contact with a human body, for example, the waist and the crotch parts of
excretion-treating materials such as a paper diaper.
The thickness of the above-cited films preferably is from 10 to 200 .mu.m,
and the thickness of the sheets preferably is more than 200 .mu.m.
These films or sheets are prepared by the general methods such as
extrusion, T die, or inflation.
To the resin obtained in this invention, other thermoplastic resins or
elastomers can be added within the scope of the objects of this invention.
For example, there can be used polyvinyl chloride, ethylene-vinyl acetate
copolymer, polyester copolymer, styrene-type elastomer, polybutadiene,
vinyl chloride-type elastomer, acryl-type polymer, polyamide, polyimide,
polyamideimide, or polyphenylene sulfide.
The thermoplastic polyurethane resin composition obtained in this invention
can be prepared by the various well-known methods. For example, after
blending raw materials homogeneously in a mixing machine such as tumbler
or Henschel mixer, the resulting mixture of the above-cited raw materials
is supplied to a uniaxial or biaxial extruder, melted and kneaded to
prepare it in the form of pellets.
The larger the amounts of the modified olefin resins (B) added to the resin
of this invention, the more improved their flexibility, smooth touch, and
pliability, but the more decreased in heat-stability and permanent set.
Thus, the amount of the above-cited component (B) to be added should be
determined according to the purpose for which the resin composition of
this invention is to be applied. When the amount of component (B) is less
than 1 part by weight, the effects of this invention is hardly obtainable.
Because the modified polyolefin resins (B) having good compatibility with
the polyurethane resins (A) are blended therewith, the polyurethane resin
composition of this invention still holds an excellent tensile strength,
fracture elongation, cold resistance, and wear resistance, which are the
specific properties of polyurethane resin. Moreover, the thermoplastic
polyurethane resin composition of this invention acquires excellent
flexibility, pliability, feeling or smooth touch, and non-tackiness when
molding or rolling the films made of the resin.
The films obtained from the polyurethane resin of this invention are quite
suitable for the elastic films for waist-gathering or leg gathering of the
paper diaper.
This invention will be described in greater detail with reference to the
following examples But, this invention is not limited thereto. In the
examples, all parts are by weight.
REFERENCE EXAMPLE 1
Preparation of olefin copolymer containing carboxyl group
Hundred (100) parts of ethylene-butene-1 copolymer (the above-cited
TAFMER-A4090), 0.5 part of 1,3-bis (tert.-butyl peroxypropyl) benzene, and
1 part of maleic anhydride were mixed homogeneously. Next, the mixture was
kneaded, and pelletized by an extruder at a cylinder temperature of
220.degree. C. Thus, olefin copolymer containing carboxyl group was
obtained.
This olefin copolymer was confirmed to contain 0.75 part of grafted maleic
acid anhydride per 100 parts of ethylene-butene-1 copolymer according to
the infrared spectrometry. This was named copolymer (I).
REFERENCE EXAMPLE 2
Preparation of olefin copolymer containing epoxy group
Hundred (100) parts of ethylene-butene-1 copolymer (above-cited
TAFMER-A4090), 0.5 part of dicumyl peroxide and 2 parts of methacrylic
acid glycidyl ester were homogeneously mixed. Next, the mixture was
kneaded, and pelletized by a biaxial extruder at a cylinder temperature of
200.degree. C. Thus, olefin copolymer containing epoxy group was obtained.
This olefin copolymer was confirmed to contain 1.25 parts of grafted
methacrylic acid glycidyl ether per 100 parts of ethylene butene-1
copolymer, according to the measurement of the amounts of grafted
methacrylic acid glycidyl ether. This was named copolymer (II).
EXAMPLES 1 TO 7
The mixture was kneaded and pelletized with a 50 m/m extruder at
190.degree.to 200.degree. C., which was mixed with thermoplastic
polyurethane resins (PANDEX T-5167, and PANDEX T-6090, manufactured by
Dainippon Ink and Chemicals, Inc.), the above-cited copolymers (I) and
(II), small amounts of calcium carbonate as a filler, and aliphatic acid
amide as a lubricant in proportions shown in Table 1.
The test pieces in the form of films (thickness; 30 to 40 .mu.m) were
obtained from the above cited pellets by an inflation type extruder {65
m/m). The test results obtained are shown in Table 1.
COMPARATIVE EXAMPLES 1 TO 3
Similar evaluation to the preparation of above cited Examples, the mixed
product of thermoplastic polyurethane resins (PANDEX T-5167, manufactured
by Dainippon Ink and Chemicals, Inc.), and SBR resins (T-R2000
manufactured by Japan Synthetic Rubber Co Ltd ) was obtained. This product
and each of the above-cited single polymer were pelletized, filmed, and
tested with the same procedure as in the above-cited Examples. The results
obtained are also shown in Table 1.
TABLE 1
__________________________________________________________________________
Material/Property Ex. 1
Ex. 2
Ex. 3
Ex. 4
Ex. 5
Ex. 6
Ex. 7
C. Ex. 1
C. Ex.
C. Ex.
__________________________________________________________________________
3
PANDEX T-5167
Urethane
99 80 50 80 80 100
PANDEX T-6090
Urethane 80 50 80
T-R2000 SBR 10 100
Copolymer I Modified
1 20 50 20 50
Olefin
Copolymer II
Modified 20 20
Olefin
Calcium carbide
Filler
10 5 5 5 5 0 5 10 5 5
Aliphatic acid
Lubricant
0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3
amide
50% Modulus (Kg/cm.sup.2)
50 45 33 47 40 30 45 70 65 55
Tensile strength
(kg/cm.sup.2)
400 450 235 440 390 225 380 350 500 220
Fracture elongation
(%) 400 450 510 460 470 570 465 300 390 380
Permanent set
(%) 7 4 7 4 3 6 3 9 5 10
Film forming property.sup.1)
B A B A A B A B C B
Pin hole.sup.2) C B B B B C B C C B
Foaming.sup.2) C B B B B B B C B B
Tackiness.sup.2) B A B A A C A B D D
Flexibility of film.sup.1)
B A B A A C A C B D
Stretching property
B A C A A C A C B D
of film.sup.1)
Feeling of film C A B A A B A D D D
(smooth touch).sup.1)
Frill formation in film
C A C A A C A D D D
(smooth touch).sup.2)
__________________________________________________________________________
.sup.1) The standard of evaluation:
Aexcellent, Bgood, Cslightly bad, Dbad,
.sup.2) The standard of evaluation:
Anone, Bfew, Ca few, Dmany
Flexibility of the films: The softness of the films were evaluated when
rolling the film.
Smooth touch of the film: The feeling when touching the film was
evaluated.
Frill of the film: The degree of frill remained after clenching the film
was evaluated.
Top