Note: Descriptions are shown in the official language in which they were submitted.
This invention relates to cold or hot water supply pipes
composed of a poly-l-butene resin composition having excellen-t
resistance and pressure-resistant strength against cold or hot
water having sterilizing chlorine dissolved therein.
Metallic pipes such as zinc-placed steel pipes, copper
pipes and lead pipes have heretofore been used as pipes for supplying
cold or hot water. The steel pipes have the defect that rust is
formed to generate red or black water. The copper pipes have the
defect that pin holes are generated owing to electrolytic corrosion,
or blue water occurs as a result of rust formation. ~lence, new
piping materials have been desired. To some extent, plastic pipes
such as pipes made of polyvinyl chloride, polyethylene and poly-l-
butene which do not develop rust or pinholes owin~ to electrolytic
corrosion have already come into practical use. In particular,
poly-l-butene is now evaluated as one of the most suitable resins
for water supply pipes because of its excellent pressure-resistant
strength, internal pressure creep durability at high temperatures,
high and low -temperature properties, abrasion resistance, and
flexibility.
; 20 Like other synthetic resins, poly-l-butene also undergoes
chemical degradation under the ackion of sterilizing chlorine
added to city water, and tends to lose its inherent high
performance. This tendency becomes especially pronounced in hot
water supply pipes which are placed under high-temperature and
high-pressure loads.
To the best of the knowledges of the present inventors,
there has not been known a poly-l-butene resin composition having
~l~3~
excellent resistance (to be referred to as chlorine water resistance)
to cold or hot water containing sterilizing chlorine dissolved
therein (to be referred to as chlorine water) and excellent
pressure-resistant strength.
It is an object of this invention therefore to provide
a water supply pipe composed of a poly-l-butene resin composition
having excellent chlorine water resistance.
Another object of this invention is to provide a water
supply pipe composed of a poly-l-butene resin composition having
excellent chlorine water resistance and excellent pressure
resistance in the state of being in contact with chlorine water (to
be referred to simply as pressure resistance).
Still another object of this invention is to provide a
water supply pipe composed of a poly-l-butene resin composition
which has excellent surface luster and shows only a small extent
of decrease in the degree of polymerization of the poly-l-butene
polymer when it is kept in contact with chlorine water for a long
period of time.
A further object of this invention is to provide a water
supply pipe composed of a poly-l-butene resin composition having
excellent chlorine water resistance and pressure resistance which
is suitable for use as a material for pipes used to supply cold or
hot water having a minor amount of sterilizing chlorine dissolved
therein.
Other objects and advantages of this invention will
become apparent from the following description.
The invention provides a cold or hot water supplying
pipe capable of supplying cold or hot water containing sterilizing
~, 2 -
"'"' "1.
~'~3~
Chlorine dissolved therein, said pipe being composed of a
resin composition comprising a poly~ utene polymer and at least
one hindered phenol selected from the group consisting of
(a) 3,5-di-tert-butyl-4-hydroxybenzoates of the following
formula
(CH3)3C ~ o
HO ~ ~ C-O-R
(CH3)3
wherein R represents an alkyl group having 1 to 18 carbon
atoms or an aryl group having 6 to 18 carbon atorns;
(b) 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-
hydroxybenzyl)benzene,
(c) 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)
isocyanurate,
(d) tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate,
(e) n-octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-
propionate,
(f) a nickel salt of a monoethyl ester of bis(3,5-di-tert-
butyl-4-hydroxybenzylphosphonic acid),
(g) 2~2l-dihydroxy-3l3l-di(~-methylcyclohexyl)-5t5~-di
methyl-diphenylmethane,
(h) 4,4'-thiobis(3-methyl-6-tert-butyl-phenol),
(.i) 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butyl-phenyl)-butane,
(j) tetrakis(methylene-3-(3,5-di-tert-butyl-4-hydroxy-
phenyl)propionate)methane, and
(k) 4,4'-methylene-bis(2,6-di-tert-butyl-phenol) in an amount
effective to provide said polymer with resistance to chemical
degradation from the effects of said sterilizing chlorine.
3 -
~3~
The resin composition of the supplying pipe according to
the invention preferably further comprises at least one compound
selected from the group consisting of
(1) 2,6-tert-butyl-p-creosol
(m) tris(2,4-di-tert-butyl-phenol) phosphite, and
(n) tocopherol.
The invention also provides a method for providing a
poly-l-butene resin composi-tion with chlorine water-resistance and
pressure-resistance for both cold and hot water having a minor
amount of sterilizing chlorine dissolved therein, said method
comprising incorporating in said poly-l-butene resin composition a
stabilizing effective amount of at least one hindered phenol
selected from the group consisting of
(a~ 3,5~di-tert-butyl-4-hydroxybenzoates of the following
~ormula
(CH3~3C "
EIO ~ C-O-R
(CH3)3
wherein R represents an alkyl group having 1 to 18 carbon atoms
or an aryl group having 6 to 18 carbon atoms;
(b~ 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxy-
benzyl~benzene,
(c~ 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-
isocyanurate,
(d) tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate,
~ e) n-octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-
: propionate,
(f) a nickel salt of a monoethyl ester of bis(3~5-di-tert-
:~ - 3a -
'``~`'
2~
butyl~4-hyd.roxybenzylphosphonic acid),
(g) 2,2' dihydroxy-3,3'-di(~-methylcyclohexyl)-5,5'-di-methyl-
diphenylmethane,
(h) 4,4' thiobis(3-methyl-6-tert-butyl-phenol),
(i) 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butyl-phenyl)butane,
(j) tetrakis(methylene-3-(3,5-di-tert-butyl-~-hydroxy-
phenyl)propionate)methane, and
(k) ~,4'-methylene-bis(2,6-di-tert-butyl-phenol)
in an amount effective to provide said polymer with resistance to
chemical degradation from the effects of said sterilizing chlorine.
The invention further provides a method for providing a
poly-l-butene resin composition with chlorine water-resistance
and pressure-resistance for both cold and hot water having a minor
amount oE sterilizing chlorine dissolved therein, said method
comprising incorporating in said poly-l-butene resin composition
a stabilizing effective amount of at least one hindered phenol
selected from the group consisting of (a) to (k) defined above in
an amount effective to provide said polymer with resistance to
chemical degradation from the effects of said sterilizing chlorine.
The hindered phenols (a) to (k) used in the present
invention are compounds known as antioxidants or ultraviolet
absorbers.
Investigat.ions of the present inventors have shown that
while very many hindered phenols have been known heretofore, only
the above-specified compounds (a) to (k) can improve the chlorine
water resistance or pressure resistance of poly-l-bu-tene polymer
to a fully satisfactory degree and other hindered phenols are
useless for this purpose, although no clear reason has yet been
.~ - 3b -
i , .
~3~2~
assigned to it.
The specific structures of the hindered phenols (a) to
(k) used in this invention are shown below.
(a) 3,5-Di-tert butyl-4-hydroxybenzoates
These compounds are represented by the following formula
(I).
:~ 3c -
; i., ,;~ ,
~3~2~3
_ 4 --
(CH3)3c o
H0 ~ C-0-R (I)
(cEI~)3c
wherein R represents an alkyl group having 1 to
18 carbon atoms or an aryl group having 6 to 18
carbon atoms~
In formula (I) above, the Cl ~ C18 alkyl group
may be linear or branched, and includesi for example9
methyl, ethyl~ propyl, butyl, pentyl, hexyl~ heptyl~ octyl~
nonyl, decyl, undecyl, dodecyl, hexadecyl and octadecyl.
Examples of the C6 - C18 aryl group are phenyl, naphthyl
and diphenyl or alkyl-substituted aryl groups resulting
from the substitution of the above aryl groups by 1, 2 or 3
alkyl groups having 1 to 12 carbon atoms provided that the
~ total number of carbon atoms in the substituted aryl groups
: does not exceed 18. Specific examples of the alkyl-sub~
stituted aryl groups are 3,5-di-tert-butylphenyl, 2,6-di-
ter-t-butylphenyl, 2,4-di-tert-butylphenyl, 2l4,6-tri-tert-
butylph~nyl, 2,6-dimeth~ylphenyl, and 2,6-di-tert-butyl-4-
methylphenyl .hus, examples of the 3,5-di-tert-butyl-4-hydroxy-
:~ 20 benzoates of formula (I) include methyl 3,5-di-tert-butyl-
. 4-hydroxybenzoate, propyl 3,5-di-tert-butyl-L~-hydroxy-
: benzoate, octyl 3,5-di-tert-butyl-4-hydroxybenzoate~ dodecyl
3,5-di-tert-butyl-4-hydroxybenzoate, hexadesyl 3,5-di-tert-
butyl benzoate, 3,5-di-tert-butylphe~yl 3,5-di-tert-butyl-4-
hydroxybenzoate, 2,5-di-tert-butylphenyl 3,5-di-tert-butyl-
4~hydroxybenzoate, 2,4,6-tri-tert-butylphenyl 3,5-di-tert-
butyl-4-hydroxybenzoate, 2,'~-di-tert-butylphenyl 3,5--di-
: tert-butyl-4-hydroxybenzoate, and 2,6-dimethylphenyl 3,5-di-
tert-butyl-4-hydroxybenzoate.
~; ~ 30 : (b) 1,3,5-~rimethyl-2,4,6-tris(3,5-di-tert-butyl-4-
~: hydroxybenzyl)benæene
,
' ~ :
~3~
OH
t~Bu ~ , t^Bu
CH2
CH3 ~ ~ aH3
t Bu ~ ~ CH2 ~1 CH2 ~ , t Bu
HO ~ ~ C 3 1 ~ OH
t Bu t-Bu
(In the above and subsequent formulae, t.Bu
represents a tert-butyl group~
(c) 1,3,5-tris(4-tert-Butyl-3-hydroxy-2,6 dimethyl-
benzyl ) is o cyanate
toBU
~ OH
3 ~ CH3
CH2
0~ O
CH3 I CH
C~ CB2
OH OH
(d) tris( 3, ~Di-tert-butyl-4-h;Tdro3{;ybenzyl)iso-
cyanurate
~:
: :
;
-- 6
OH
t-Bu ~ , t~Bu
ICH2
O~ f o
t.Bu ~ ~ CH2~ ~ `CH2 ~ , t~Bu
HO ` OH
t-Bu t-Bu
(e) n-Octadecyl 3-(3,5-di-tert-butyl-4-hydroxy-
phenyl)propionate
t Bu
HO ~ ~ CH2CH2COOc18 37
t^Bu
(f) Nickel salt of a monoethylester of bis(3,5-di-
tert-butyl-4-hydroxybenzylphosphonic acid)
( B~CB2-P-O ) l~i
(g) 2,2'-dihydroxy-3t3'-di(~-methylcyclohexy1)-5,5'-
dimethyl-diphenylmethane
H OB~
: CH3 CH3
~3~3
_ 7
(h) 4,4=Thiobis(3-methyl-6-tert-butylphenol)
,CH3 ,t-Bu
HO ~ S- ~ OH
t-Bu CH3
(i) 1,1,3-~ris(2-methyl-4-hydroxy-5-gert-butyl-
phenyl)butane
3 ~ OH
CH3 l ll
HO ~ CH -CH3-CH t-Bu
t-Bu ~ CH3 ~ t.Bu
aH3 OH
(j) ~etrakis~methylene 3-(3~5-di-tert-bu-tyl-4-hydro-
xyphenyl)propionate~methane
t Bu
C (cH2ococ~I2cH2~oH
-t-Bu
(k) 4,4'-Methylenebis(2,6-di-tert-butylphenol)
t.Bu t.Bu
HO~CE2~0H
t.B~ t.Bu
The poly-l-butene polymer used in this inven-tion
is preferably a homopolymer of l-butene, a copolymer of at
least 90 mole % of l-butene and no-t more than 10 mole% of
another a-olefin~ or a mixture of at least 50% by weight of
the above homopolymer or copolymer with not more than 50/0
by weight of another a-olefin polymer. Examples of
.
~3~3
~-olefins other than l-butene are ethylene, propylene, 4-methyl-1-
pentene, l-hexene and l-octene. The poly-l-butene polymer used in
this invention especially preferably has a melt flow rate (to be
abbreviated MER) of 0.1 to 50 g/10 minutes (measured in accordance
with AST~ D-1238N). The poly-l-butene polymers used in this
invention and methods for their manufacture are described, for
example, in the specifications of United States Patents Nos.
3197452, 3219645, 3362940, 3244685, 3356666, 3907761 and 3865902.
The poly-l-butene resin composition of this invention may
contain 100 parts by weight of the poly-l-butene polymer and
usually 0.05 to 2.0 parts by weight, preferably 0.1 to 1.0 part by
weight, of at least one hindered phenol selected from the group
consisting of (a) to (k) above. If the content of the hindered
phenol is lower than the above-specified lower lirni-t, the extent of
improvement of the chlorine water resistance of the poly-l-butene
resin composition tends to be considerably small.
A group of the hindered phenols (a) to (k) used in this
invention give poly-l-butene resin compositions having improved
chlorine water resistance and pressure-resistant strength.
Investigations of the present inventors have shown the above
hindered phenols to be excellent in that the 3,5-di-tert-butyl-4-
hydroxybenzoate (a) give the poly-l-butene resin composition of
the invention which undergoes little degradation at its surface of
contact with chlorine water when kept in contact with chlorine
water, and the hindered phenols (b) to (k) give the poly-l-butene
resin composition which has a relatively high degree of poly-
merization and little decreases in its degree of polymerization
when kept in contact with chlorine water~ In Examples given
- 8 -
~l .
,.~ ~ '
~2~
hereinbelow, the degradation of the contacting surface is evaluated
by measuring the gloss of the resin surface, and the degree of
polymerization, by
':
'
'
.,
`~
:;``: ~ :
~, ~
- 8a -
~2~ 3
measuring the solu-tion viscosity of the resin composition.
Preferably, the resin compo sition of this inven-
tion contai.ns at least one 3~ 5-di~tert-butyl~4-hydroxy-
benzoate (a) and at least one of the hindered phenols (b)
5 to (k).
The resin composition of this invention desirably
contains at least one of co~pounds (1) to (n) shown below.
(1) 2,6-di-tert-butyl-p-cre~ol
t-Bu
H0 ~ CH3
t-Bu
(m~ tris(2~4-di-tert-butyl-phenyl)phosphite
t.Bu
( t~Bu ~ 0 ~ P
(n) tocopherol(a-, ~ or S-tocopherol, or a
mixture of these)
The resin Composition of this invention further
containing at least one of the co~pounds (1) to ~n) is
superior in that it has a higher degree Of polymerization
than the resin Composition of this invention not containing
-these compounds. ~he compounds (1) to (n) effectively
prevent the poly-l~butene polymer from being degraded in
the molten State by o~ygen and heat when it iS mixed with
the hindered phenols (a) to (k). The resin composition of
this invention which ~urther Contains at least one compound
~rom the group of (1) to (n) Contains at least one of (1)
: to (n) in an amount of usually 0.01 to 1.0 part by weight~
preferably 0.05 to 0.5 part by weight~ per 100 parts by
weight of the poly-l-butene polymer. When the content of
the compound (1) to (n) is less than 0.01 part by weight~
_ 10
scarcely an~ effect is obtained of incorporating such a
compound (1) to (n). I~, on the other hand, it exeeds
1.0 part by weight, -there is a tendency to the formation
of a resin composition having a reduced tensile yield
stress~
According to this invention, the resin composition
further containing at least one of the compounds (1~ to (n)
preferably comprises at least one of the 3,5-di--tert-butyl-
4-hydroxybenzoates (a), at least one hindered phenol
selected from the group consisting of the compounds (b) to
(k) and at least one compound selected from the group of
(1) to (n); or the compound (b~, the compound (e), the
compound (j) and at least one compound selected from the
group of (1) to (n).
~he aforesaid preferred resin compositions o~
this invention have improved chlorine wa-ter resistance both
at the surface portion of a shaped articlea~d at the entire
porting of a shaped article of resin, and exhibit reduced
degradation of the polymer during molding~
Various known methods can be used to mix the poly-
l-butene polymer with the compounds (a) to (n). For example,
the individual ingredients are mixed by a ribbon blender or
a Henschel mixer and then granulated by an extruder. Or
they may be directly melted and mixed by a Banbury mixer,
a kneader, a two-roll mill, etc. and then granulated by an
extruder.
As required, other ultraviolet absorbers, mold-
proof agents, rust inhibitors, lubricants, fillers, pig-
ments, dyes, heat stabilizers, etc. may be incorporated in
the poly-l-butene resin composition of this invention.
Rust ~ormation on me~ting and processing machines caused by
the catalyst residue can be conveniently inhibited by using
as the rust inhibitors a metal salt of a higher ~atty acid,
or a double compound of the general formula
M ~ly(oH)2x+3~-2z(A)z aH2
wherein M represents Mg, Ca or Zn, A respresents
a divalent anion~ x, y and z are positive
numbers, and a is 0 or a positive number~
Since the resin composition of this invention has
excell~llt chlorine water resistance ancl pressure-resistant
strength~ it can be conveniently used as a material for
pipe systems adapted for supplying water having chlorine
dissolved therein, ~or e~ample tap water, or no~-potable
industrial water sterilized with chlorineO
A water supply pipe may be molded from the poly-
l-butene resirl composition of this inven-tion b~, for example~
melting the pol~ butene pol~mer having incoxporated
therein at least one compound selected fro~ (a) to (n) at
a temperature of 150 to 300C in an extruder, extruding
the molten mixture through a die, sizing the extrudate,
cooling the extrudate with cooling water at a temperature
of 5 to 50C, and cutting or winding up the cooled product
through a take-up device. ~he ex-truder may generally be a
single~screw metering t~pe extxuder. ~he die ma~, ~or
example, be of a straight head type, a cross head type or
an offset type~ ~he sizing ma~ be carried out by a sizing
plate method, an outside mandrel method~ a sizing box
method or an inside mandrel method. A pipe coupl-
ing joint may be molded by using a combination of
an ordinary inaection molding machine and Q mold or a com-
bination of a blow molding machine and a mold, and a hot
water storage tank ma~ be molded by using a combination of
a blow molding machine and a moldO
~he poly-l-butene resin composition o~ this in~en-
tion can be used widely in cold and hot water supply systemsbecause it has improved ~hlorine water resistance while
retaining superior pressure-resistant strength, internal
pressure creep durability at high temperatures) high and
low temperature properties and abrasion resistance in-
5 herent to the poly-l-butene polymer.
~he following examples illustrate the presen-t
invention in greater detail.
Example 1
One hundred parts by weight of poly-l-butene (MFR
0.8 g/10 min.' ASTM D-1238N); manufactured by Mitsui Petrochemical
Industries, Ltd.), 0.15 part by weight of calcium stearate, 0.05
part by weight of synthetic hydrotalcite (DHT-4A, a trademark)
and 0.4 part by weight of each of the compounds shown in Table 1
were mixed in a Henschel mixer, melted and extruded at 230C and
then granulated by an extruder having a screw diameter of 20 mm.
The resulting pellets were melted for 10 minutes by a hot press at
200C, and then pressed by a cold press at 30C for 3 minutes to
form a press sheet having a thickness of 1 mm. Test pieces,
10 mm x 150 mm in size, were cut off from the press sheet. Each
test piece was set on a holder, and dipped in a vessel in which
chlorine containing water having an effective chlorine concentration
of 100 ppm and a temperature of 90C was passed at a rate of
1 liter/hour. The gloss (angle of incident light 45) and [~]
(in decalin at 135C) of each test piece with the lapse of time were
measured.
Immediately after molding, all test pieces had a gloss
in the range of 90 to 95%. The results are summarized in Table 1.
- 12 -
,~;i `
Table 1
_ ___ _ Gloss (%) ~] (d~/g)
____ ._ _.____ __ __. ___ _. _
Run No. Compound In the In the Initial In the
in- 4th 8th value 8th week
corporated week week
_
1 (a)-l 85 76 3.2 1.7
2 (a)-2 80 70 3.1 1.5
3 (b) 35 6 4.2 3.2
4 (c) 30 5 4.5 3.6
(d) 25 6 3.8 2.9
6 (e) 29 6 4.1 3.0
7 (f) 76 8 4.6 3.6
8 (g) 23 5 4.6 3.5
g (h) 23 6 4.2 3.4
(i) 60 6 3.7 2.9
11 (j) 9 5 4.3 2.8
12 (k) 45 12 4.7 1.0
13 (1) 57 25 4.6 3.4
14 (m) 25 5 4.6 0.8
(n) _70 10 4.5 1.0
~ _ ~ _ ~
In the table, compound (a)-l is 2,4-di-tert-butyl-phenyl
3,5-di-tert-butyl-4-hydroxybenzoate, and compound (a)-2 is n-
hexadecyl-di-tert-butyl~4-hydroxybenzoate.
The compounds used in the above experiments were all
commercially available compounds which are sold under the ~ollowing
trademarks:
(a)-l: Tinuvin 120*
(a)-2: Cyasorb UV-2908*
(b): Irganox 1330*
(c)o Syanox 1790*
(d): Goodrite 3114*
(e): Irganox 1076*
(f): Irgastab 2002*
(g): Nonox WSP*
(h): Santonox R*
*Trade Mark
- 14 -
(i): ~opanol CA
Irganox 1010
(k) Antioxidant 702
(1): BH~
(m): Irgaphos 168
(n): vitamin E
~8lY~ yL=I_~y_~e~
Example 1 was repeated except that each of the
compounds indicated in ~able 2 was used instead of each of
the compounds indicated in Table lo The results are shown
in Table 2.
.
able 2
Compara- Compound G10BS (/0) 1 _ r~ ~ ~d~
tive in- In the In the Initial In the
Example corporated 4th 8th value 8th
week week week
_ _ _ _ _
1 Not added 7 5 1.9 0.4
2 P 6 5 2.8 0~6
3; q 8 c; 2~6 Oa 7
4 r 6 5 3.3 0~6
s 6 5 _ 3.7 1.6
p: 2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-5-
chlorobenzotriazole
: q: bis(2,2,6,6~tetrame-thyl-4-piperidyl)sebacate
. r: dis-tearyl thiodipropionate
s: pentaerythritol tetra(~-laurylthiopropionate)
Examples 2 to 4
Example 1 was repeated except that 0.2 part b-y
weight of each of the compounds indicated in Table 3 was
: used instead of 0.4 par.t by weight of each of the compounds
: : indicated in Table 1. ~he results are shown in Table 3.
::
~o
' .
~ 3
- 15 -
Example CompoundGloss (ojo) _ rnl (dB/~)
incorporated In the In tlie Initiai1 In the
: 4th 8th value 8-th
___ _ ~ ~ r _ _ week week _ ~ week
2(a3-1 and (b) 90 81 4~0 3.o
3(a)-2 and (c) 90 80 4~2 3.1
I _ _ (b) ~nd (k).~ _ _ 4.6
~ he compounds indicated in ~able 3 were commercial-
ly available under the tradenames shown below rable 1,
Examples 5 to 9
Example 1 was repeated except that 0~2 part by
weight of each of the compounds indicated in ~able 4 was
used instead o~ 0.4 part by weight o~ each of -the compounds
indicated in Table 1. The results are shown in ~able 4.
~able 4
- - - Glosc ~ r~l (d _ _
Ex- Compound incorporated In the In the Initial In the
ample 4th 8th value 8th
week week week
_. ~ .
: 5 (a)~l, (f) and (m) 90 9o 4O8 4~4
6 (a)-l, (b) and (k) 9o 90 4~7 4>3
7 (a)~l, (b) and (n3 9o 90 4.7 4.3
8 (a)-l, (b) and (m) 9o 9o 4.9 4~5
9 (a)-1, (b) and (1) 9o 90 _ _ 4.2
The compounds indicated in Table 4 were com-
mercially available under the tradenames indicated below
Table 1.
Example 10
Example 1 was repeated except that the four
compounds indicated in ~able 5 were used in the indicated
amounts instead o~ 0.4 part by weight o~ each of the
~L2
-- 16 --
compounds shown in Table 1. The results are shown in
Table 5~.
Tabl e 5
Compounds _ Glo s s (~_ --14/~)
(parts by weight) In the In the Initial In the
4th week 8th week value 8th week
___ _ _
(b) (o. ~)
(e) (0~ 3) 85 65 4~6
(i) (0.3)
(1) (0.1)
._ _ ___ _ _.
~'
