Note: Descriptions are shown in the official language in which they were submitted.
'91-1~9-~'~ 15:1 1 T~l~'EDH Ll~ PFIrENr OFFICE P.'l
~5~
~OVE~ POLYURETHANE AND MErrHOD OF PR~PA~ING THE S~ME
~AC~GROUND O~ TEIE I~VENTION
1. ~ield of the lnvention
S This invention relates to a novel polyure-thane, in
particular a novel polyurethane comprising a modified
lignin as a haLd segment tharein, ~nd a meth~d of
preparing the same.
2. Disclosure of the Prior Art
In the past, there were known polyurethanes of many
kinds. I~ general, these polyurethanes could be prepared
by stoichiometrically reacting polyol or polyester with
diisocya~te in accordance with a so-called prepolymer
method or direct preparation method.
Recently, Japanese Patent Public Disclosure No.
~89823/1989 describes that an improved polyurethane is
obtained by using a cellulosic substance, hemicellulosic
substance and lignin substance, which are contained in a
natural by-product or ayricultural was~e product, as a
hara segment in the polyurethane, whereby mechanical and
thermal properties of the polyurethana can be improved
and a low-cost polyurethane can be prepared.
However, since kraft lignin has a large molecular
weight, the viscosity of kraft lignin di~solved i~
polyeth~lene glycol is high, and furthermore it is less
compatible with dipheny}methane diisocyanate. Thus,
uniform polyurethane cannot be obtained.
Now, a wood tar distillation residue from a
'91--i~l9--~" lC '~l rH~'E L11~1 L~ H I E~ FF LCE F' . 5
2~
hroad- leaved tree and needle-leav~d tree. s~lch as
eucalyptus, Caribbean pine or the like c~n bc pxoduced
abundantly as an industrial b~product in a ~anufacturing
industry for car~on m~terials or the like, but -the way to
utilize it is yet less. In paxticular it is a~sired to
effectively utilize a modified lignin which is rnuch
contained in the residue
SUMMARY OF TI~E INVENTION
It is an o~ject of -~his invention to provide
polyurethane in which a modified lignin is effectively
used as a raw material there~o~e, and to pro~ide a method
of preparing the same.
The above ob~ ect is accomplished by proviaing
polyurethane which comprises a modified lignin as a hard
segment, or comprises a moaified li~nin as a hard segment
and a polyol compound as a soft segment.
The above ohject is also accomplished by providing a
method of preparlng polyurethane which comprises reacting
a modified lignin, diisocyanate and a polyol compound to
form the poly~rethane comprising the modified lignin as a
hard se~ment.-
~he thus-obtained polyuxethane comprising the
modified lignin as the hard segment has good mechanical
and thermal propert~es as compared with the prior
polyurethane In aadition, the inventive polyurethane is
more economical than the prior polyurethane and improves
environment.
~ lJY-_CJ lC,:S~ rH~ELJH ~H~ IE~`ll OFF~C~ P,~
~5~
DETAILED DESCRIPT:LON OF PRE~ERRE~ EMBODIMENTS
Polyurethane according to this invention inoludes a
hard segment region at least a part of which is formed by
a modi~ied lignin and a so~t ~egment region which i~
constructed by a long chain diol residue component. In
addition, the polyurethane according to this invention
includes a polyol compound in the soft segment reg.ion.
The modified lignin which is ~sed in this invention
~an be obtained ~rom a wood tar distillation residue which
is forme~ due to dry distillation of the broad-leaved
tree or needle-leaved tree. The thu~-obt~ined modified
lignin (the wood tar distillation residue) may be a
modified li~no-cellulose.
The modifed lignin in this invention may have a
molecular weight of about 300 to about 2,000, a hydroxyl
group content of about 3 to about 20 mmol/g and a
carboxyl group content-of about 0.2 about 2.0 mmol~g.
In this invention, there is used a solvent-soluhle
modifed lig~in.
The modified lignin in this in~ention has, for
example, a number average molecul~r weight of 540 and a
weight average molecular weight of 1,300 In contrast to
this invention, lignin in the prior art, for example,
kraft lignin has, for example, a num~er average molecular
weight o 1,200 and a weight average molecular weight of
2,200. Since the molecular weight of the modi~ie~ lignin
is very lower than that of the pxior lignin, viscosity of
a solution of the modified lignin in polyethylene glycol
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19-~'5 15:5~ T~liED~ Lf`~ RrE~`II U~FIC~ P.7
is lower than that of the prior L;gnin. In addition, the
modified lignin is compatible w~th diphenylmethane
diisoc~anate and can be unrestric-tedly dissolved.
Therefore, by using an appropria-te amount of the modified
liynin, it is possible to prepare the uni~orm
polyurethane as compared with the polyurethane obtained
from tha prior li~nin.
In this invention, it is pre~erred to prep~re the
polyurethane according to ~he so-called prepolymer
method. Prepolymer of polyurethane according to this
inve~tion can be prepared by ~irst aissolving the
modi~ied liynin in ~he polyol compoun~, adding the
diisocyanate component -to the ~olution with stirring and
allowing these components to polymerize. A ~ilm ~nd
resin can be o~tained b~ curing the thus-obtained
prepolymex with a catalyst or hea~ing. In addition, a
foam can be obtained by adding water (or a blowing
agent), a foam stabilizer and a catalyst to the above
prepolymer and allowing it to react.
Polyisocyanate used in this i~vention is the same as
that used in preparing the prior polyurethane. ~he
polyuretha~e can include, for example, an aromatic
isocyanate such as diphenvlmethane diisocyanate,
toluylene diisocyanate or the like; an aliphatic
isocyanate such as hexamethylene diisocyanate or the
like; and a heterocyclic isocyana~e.
~urthermore, the polyol compound used in this
invention i5 the sa~e as that used in preparing the prior
ELlri L~ IE~`Jl UF-t'~
2i~.5~
polyure~hanF~ Th~ polyol compound can include, for
e~ample, polyether se~ies such as poly~thylene glycol,
polypropylene glycol or the like and a synthetic polyol
c~mpouna of polyester series su~h as adipate,
polycaprolactone or the l:ike.
For the polymerization catalyst, convenkional amine
and tin series catalyst can be used.
For the foam stablizer, conventional ~ilicone series
such as silicone, a block copolymer o~ dimethyl
polysiloxame and polyether or the like can b~ used.
The proportion of the polyol compound to -the
mo~ified lignin to be uséd is ~ to 5,000 pa~ts by ~eight,
p~eferably 0 to 3,000 parts by weigh-t of ~he polyol
compound, based on 100 parts by weight o~ the modified
lignin.
Also, the proportion o~ the diisocyanate -to be used
is 10 to 1,000 pa~ts b~ weight, preferably 10 to 900
parts by welght, based on 100 parts b~ weight of the sum
o~ said modifiea li~nin and said polyol compound. In
case of ma~ing the foam, the water and ~oam stabilizer
~re used in an a~ount of 0.1 to 20 parts by weight,
preferably 0.5 to 10 part~ by weight and 0~001 to 0.5
parts by weight, pre~erably 0.02 to 0.25 parts by weight,
respectively, based on 1 no paxts b~ weight of the sum o~
said modified ligni~, said polyol compound and Saia
diisoc~anate.
The preparation o~ polyurethane according to this
invention can be carried out by dissolving the modified
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'91-EIY-~C 15:53 T~KEDI~I LHW ~ PRiENT OFFICE p,9
lignin i.n the polyol ~ompound which is used both ~or
solvent and for re~ctant, a~ding di.isocyan~te to the
obtained solution and allowing these components to react.
For the other solvent, for example, tetr~hydro-uran~
S aioxane or the like can be us~d. In -this case, it is
possible to dissolving the modified lignin and polyol
compound in the solven-t, ~dding diisocyana-te to the
obtained solution and allowing them to react. ~he
pxoportion of said polyol compouna to be used in ~his
reactlon is 0 to 95 parts by weight, pre~erably 0 to 90
parts by weight, based on 100 parts by weight o the
moaified lignin.
According to this invention, in case of using the
polyol compound as a solvent, it is possible to obtain
the polyurethane comprising 5 -to 25 ~ by weight,
preferably 10 to 25 ~ by weight oE the modi~ied lignin; 5
to 90 ~ by weight, pre~exably 10 to 70 % by weight, o
the polyol compound; and 5 to 90 ~ by wei~ht, pre~erably,
10 to 70 ~ by weight, o~ s~id diisocyanate. In case of
using the solvent ~ther than the polyol compound, it is
possible to obtain the polyurethane comprising 5 to 25
by wiehgt, preferably 10 to 25 % by weight, of the
modified lign~n; 0 to 90 % by weight, preferably 5 to 70
by weight, of the polyol compound; ~nd 0 to 90 % ~y
weight, preferably 5 to 70 ~ by weight, of diisocyanate.
In general, the weight ratio of polyol/~odified lignin
in the reaction produ~t is preferably in a range o~ 0 to
20, preferably 0 to 10.
'91-E~9-2C 15:53 TI~ EDR LQW .~ P~llE~`II OFFICE P. iE~
Since the polyurethane o-E this invention includes the
modified lignin as the hard segment ~or polyurethane, it
possesses good mechanical and-thermal properties.
Furthermore, the modified lignin is uniformly contained
s as the ha~d se~ment ln the polyurethane in an appropriate
proportion, whereby it b~comes possible ko appropriately
adjust the mechanical and thermal proper-ties.
In addition, the modifed li~nin is very ch~ap, s~nce
a use application thereo~ has not been de~eloped ana thus
it has been treatea as an industrial was~e.
A1so, in the polyure~hane of this invention, it is
possible to easily control properties o~ polyur~thane by
changing the proportion of the soft segment compr.~sing
the polyol compound and the hard segmen~ comprising the
modified lignin.
~ext, this invention will be in detail aescribed
with reference to ~n embodiment thereof but is not
subject to restriction o~ the basis of the ~oltowing
description~
Example 1
A modified lignin was obtained by pyrolizing a
eucalyptus, distilling the thus-obtained tar content and
recovering a residue. ~he modi~iea lig~in has a hydroxyl
group content o~ 5.8 mmol/g, a carboxyl group content o~
0.8 mmol/g, a nu~ber average molecular welght (Mn) of
540, a weight average molecular ~Mw) of 1,200 and a
molecular-weight aistributio~ ~M~Mn) o~ 2 2. ~he
modified lignin was dlssolve.d in polypropylene glycol
iY~ r~ EL~ L~:~W ~ ilE~ )F`F L~E ~. 11
(Functionallty of 3, Molecular Weight ok 400). To 100
parts by welght of the polypropylene ~lycol solution,
diphenylme~hane diisocyanate was ~dded ln a predetermlned
amount so as to attain NCO/OH of 1.2, with stirring. Two
parts by weight of water were added as a blowing a~ent
and two parts by weight of silicone were added as a foarn
stabili2er For a catalyst, dibutyltin laurate was
used
For the ~h~s-obtaine~ polyurethane foam, compressive
strength and modulus of ela~ticity were measured. The
re~ults are shown in Table 1.
Table 1
Compressive Strength and Modulus of Elastici-ty of Foam
. . _
Compressive Mod~lu~ of
Lignin ContentStrength Elasticity
lS (~) (105Pa) (MPa~
~ 3.8~ 9~78
4.17 11.24
4~44 15.27
2~ 4.96 10.0
~0
As mentioned above, the polyuxethane according to
this invention has good mechanical strength and heat
resistance as compared with the prior polyurethane since
it uniformly contains the modified lignin as the hard
segment for polyurethane. In addition, it is possible to
adjust the mechanical strength and heat resistanca.
Furthermore, since the raw ~aterial in ~his
invention is th2 industrial waste in the carbon chemi~al
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'91-~9-~5 15 5~1 T~ ELJ~l LrlW ~ Pl ITENT OFFICE P. 12
~52~
industry, its cost is very cheap
Accordin~ly, this invention resides in that the
material which had no use i~ the past and was uselessly
renounced ls utilized as a raw material for manufac-t~ring
polyuret~ane which is at present usea in many ~iel~.
This invention attains the improvement of environment and
thus is useful.
