U.S. patent application number 09/204082 was filed with the patent office on 2001-12-27 for chlorinated vinyl chloride resin composition.
Invention is credited to ISSHIKI, MINORU, OKUHARA, TOSHIO, SUZUKI, TAKEYUKI.
Application Number | 20010056152 09/204082 |
Document ID | / |
Family ID | 18259219 |
Filed Date | 2001-12-27 |
United States Patent
Application |
20010056152 |
Kind Code |
A1 |
OKUHARA, TOSHIO ; et
al. |
December 27, 2001 |
CHLORINATED VINYL CHLORIDE RESIN COMPOSITION
Abstract
A chlorinated vinyl chloride resin composition containing a
chlorinated vinyl chloride resin which has a polymerization degree
of from 600 to 1500 prior to chlorination and a chlorination degree
of from 62 to 70 wt. %, an impact modifier, a stabilizer, a
lubricant and titanium dioxide, wherein the content of zinc in
titanium dioxide is 0.1% or less, which has improved thermal
stability.
Inventors: |
OKUHARA, TOSHIO;
(TAKASAGO-SHI, JP) ; SUZUKI, TAKEYUKI;
(TAKASAGO-SHI, JP) ; ISSHIKI, MINORU; (OTSU-SHI,
JP) |
Correspondence
Address: |
FOLEY AND LARDNER
SUITE 500 3000 K STREET NW
P O BOX 25696
WASHINGTON
DC
200078696
|
Family ID: |
18259219 |
Appl. No.: |
09/204082 |
Filed: |
December 3, 1998 |
Current U.S.
Class: |
524/497 ;
524/567 |
Current CPC
Class: |
C08K 3/22 20130101; C08L
23/28 20130101; C08L 27/24 20130101; A61P 37/08 20180101; C08L
51/04 20130101; C08K 5/57 20130101; C08L 27/24 20130101; C08K 3/22
20130101; A61P 37/00 20180101; C08K 5/57 20130101; C08K 2003/2241
20130101; C08L 2666/02 20130101; C08L 27/24 20130101; C08L 27/24
20130101 |
Class at
Publication: |
524/497 ;
524/567 |
International
Class: |
C08K 003/22 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 3, 1997 |
JP |
332894/97 |
Claims
What is claimed is:
1. A chlorinated vinyl chloride resin composition comprising a
chlorinated vinyl chloride resin which has a polymerization degree
of from 600 to 1500 prior to chlorination and a chlorination degree
of from 62 to 70 wt. %, an impact modifier, a stabilizer, a
lubricant and titanium dioxide, wherein the content of zinc in
titanium dioxide is 0.1% or less.
2. A chlorinated vinyl chloride resin composition according to
claim 1, wherein said stabilizer is at least one tin-base
stabilizer.
3. A chlorinated vinyl chloride resin composition according to
claim 1, wherein an amount of said titanium dioxide is at least 1
wt. parts per 100 wt. parts of said chlorinated vinyl chloride
resin.
4. A chlorinated vinyl chloride resin composition according to
claim 1, wherein said impact modifier is MBS or a mixture of MBS
and chlorinated polyethylene.
5. A chlorinated vinyl chloride resin composition according to
claim 1, wherein an amount of said impact modifier is from 4 to 15
wt. parts per 100 wt. parts of said chlorinated vinyl chloride
resin.
6. A pipe made from a chlorinated vinyl chloride resin composition
according to any one of claims 1 to 5.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a chlorinated vinyl
chloride resin composition. In particular, the present invention
relates to a chlorinated vinyl chloride resin composition
containing titanium dioxide which improves the thermal stability of
the composition.
[0003] 2. Prior Art
[0004] Shaped articles of chlorinated vinyl chloride resin
compositions have characteristics such as high heat resistance and
are used at relatively high temperatures at which conventional
vinyl chloride resin compositions cannot be used due to thermal
deformation. For example, the shaped articles of chlorinated vinyl
chloride resin compositions are used in the form of a pipe for hot
water by making use of the high thermal deformation temperature
which is 20 to 40.degree. C. higher than that of the shaped
articles of vinyl chloride resin compositions.
[0005] In the case of shaping, chlorinated vinyl chloride resins
have a drawback that they have inferior thermal stability to vinyl
chloride resin compositions, and thus they tend to be burnt in a
shaping process. For example, a chlorinated vinyl chloride resin is
colored when it is extrusion molded to produce a pipe for hot
water, or in some cases, it is burnt during extrusion molding.
Thus, such a produced pipe may not be commercially sold.
SUMMARY OF THE INVENTION
[0006] One object of the present invention is to provide a
chlorinated vinyl chloride resin composition having good thermal
stability, in particular, for the production of pipes.
[0007] Accordingly, the present invention provides a chlorinated
vinyl chloride resin composition comprising a chlorinated vinyl
chloride resin which has a polymerization degree of from 600 to
1500 prior to chlorination and a chlorination degree of from 62 to
70 wt. %, an impact modifier, a stabilizer, a lubricant and
titanium dioxide, wherein the content of zinc in titanium dioxide
is 0.1% or less.
DETAILED DESCRIPTION OF THE INVENTION
[0008] A vinyl chloride resin (prior to post-chlorination), which
is a raw material of a chlorinated vinyl chloride resin contained
in the composition of the present invention, has a polymerization
degree of from 600 to 1500, preferably from 600 to 1300, more
preferably from 600 to 1200. The chlorination degree of the
chlorinated vinyl chloride resin is from 62 to 70 wt. %, preferably
from 63 to 70 wt. %, more preferably from 65 to 70 wt. %.
[0009] When the polymerization degree of a vinyl chloride resin as
the raw material of a chlorinated vinyl chloride resin is less than
600, sufficient mechanical strength cannot be attained. When this
polymerization degree exceeds 1500, the processing of the resin
composition is not easy.
[0010] When the chlorination degree of a chlorinated vinyl chloride
resin is less than 62 wt. %, a resin composition does not have
sufficient heat resistance. When the chlorination degree exceeds 70
wt. %, the resin has a high melt viscosity, and thus the processing
of a resin composition undesirably encounters technical
problems.
[0011] Herein, "vinyl chloride resins" include vinyl chloride
homopolymers, and also copolymers of vinyl chloride with other
copolymerizable monomer (e.g. ethylene, propylene, vinyl acetate,
allyl chloride, allyl glycidyl ether, acrylate esters, vinyl
ethers, etc.).
[0012] The composition of the present invention is characterized in
the use of titanium dioxide containing 0.1% or less of zinc. The
use of such titanium dioxide containing the small amount of zinc
significantly improves the thermal stability of a resin
composition.
[0013] Titanium dioxide having such a low zinc content can be
produced by a chlorine method, while titanium dioxide is usually
produced by a sulfuric acid method. Titanium dioxide having such a
low zinc content is commercially available.
[0014] The amount of titanium dioxide is preferably at least 1 wt.
parts, more preferably at least 2 wt. parts, per 100 wt. parts of
the chlorinated vinyl chloride resin. When the amount of titanium
dioxide is less than 1 wt. parts, the inherent whitening effect of
zinc dioxide deteriorates, and obtained shaped articles, in
particular, pipes have decreased impact strength.
[0015] The upper limit of the amount of titanium dioxide is not
critical. Practically, the amount of titanium dioxide does not
exceed 10 wt. parts per 100 wt. parts of the chlorinated vinyl
chloride resin.
[0016] It is preferable for the chlorinated vinyl chloride resin
composition of the present invention to contain an impact modifier,
a stabilizer, a lubricant, etc. in addition to titanium dioxide so
that the composition has well balanced impact resistance and heat
resistance by taking processability into account.
[0017] An impact modifier may be any of conventionally used impact
modifiers for chlorinated vinyl chloride resins, for example, those
comprising MBS, ABS, MABS, chlorinated polyethylene (CPE), acrylic
rubber, etc.
[0018] In particular, MBS or the combination of MBS and chlorinated
polyethylene is preferably used as an impact modifier to balance
the impact resistance and heat resistance. For the same reason, the
amount of an impact modifier or impact modifiers is preferably
between 4 and 15 wt. parts, more preferably between 4 and 12 wt.
parts, per 100 wt. parts of a chlorinated vinyl chloride resin.
[0019] Stabilizers may be any conventional stabilizers for
chlorinated vinyl chloride resins such as tin-base stabilizers,
lead-base stabilizers, etc. Among them, tin-base stabilizers are
preferable. Titanium dioxide containing such a small amount of zinc
can most effectively display its effect to improve the thermal
stability, when a tin-base stabilizer is used as a stabilizer.
[0020] Preferable examples of tin-base stabilizers are alkyltin
compounds (e.g. methyltin, butyltin, octyltin, mixed metal
alkyltin, etc.). Other examples of tin-base stabilizers are
mercaptomethyltin, mercaptooctyltin, mercaptobutyltin,
dialkyltinbis(alkylmercaptocarboxylate salt), octyltin maleate,
butyltin maleate, octyltin laurate, butyltin laurate, butyltin
lauratemaleate, octyltin carboxylate, butyltin carboxylate,
etc.
[0021] The amount of a stabilizer is preferably from 1.5 to 5 wt.
parts, more preferably from 1.5 to 4 wt. parts, per 100 wt. parts
of a chlorinated vinyl chloride resin. When the amount of a
stabilizer is less than 1.5 wt. parts, the thermal stability of a
chlorinated vinyl chloride resin composition deteriorates. When the
amount of the stabilizer exceeds 5 wt. parts, the effect to improve
the thermal stability reaches the limit, and thus the thermal
stability is not improved in a degree comparable to the added
amount of the stabilizer.
[0022] Examples of lubricants are polyglycerol of di- or trioleate,
polyethylene, oxidized polyethylene, high molecular weight paraffin
waxes, etc. Among them, polyethylene waxes are preferable.
[0023] The amount of a lubricant is preferably from 1.5 to 4 wt.
parts, more preferably from 1.5 to 3 wt. parts, per 100 wt. parts
of a chlorinated vinyl chloride resin. When the amount of a
lubricant is less than 1.5 wt. parts, the composition has a high
melt viscosity, and thus its extrusion precessability deteriorates.
When the amount of a lubricant exceeds 4 wt. parts, the lubricity
of the resin against metals becomes too high, and thus the
composition may pulsate when it is discharged in the extrusion
processing process.
[0024] The chlorinated vinyl chloride resin composition of the
present invention may optionally contain other additives, which are
compounded in conventional chlorinated vinyl chloride resin
compositions, in addition to the above additives. Examples of the
other additives are acrylic processing aids, colorants, and the
like.
[0025] The chlorinated vinyl chloride resin composition of the
present invention may be prepared by any conventional methods. For
example, all the additives are added to the chlorinated vinyl
chloride resin at a time and kneaded. Alternatively, the additives
are added to the chlorinated vinyl chloride resin one after another
and kneaded.
[0026] The kneading may be carried out with any conventional
kneading machines.
EXAMPLES
[0027] The present invention will be explained in more detail by
the following examples, which do not limit the scope of the
invention in any way.
[0028] In the examples, "parts" and "%" are "wt. parts" and "wt.
%", respectively, unless otherwise indicated.
Example 1
[0029] A vinyl chloride resin having a polymerization degree of
1,000 was post-chlorinated to obtain a chlorinated vinyl chloride
resin having a chlorination degree of 67%.
[0030] MBS (Trade name "B561" manufactured by KANEKA CORPORATION)
(6 parts) and a chlorinated polyethylene having a chlorination
degree of 35% (Trade name "H135" manufactured by DAISO CO., LTD.)
(3 parts) were added as impact modifiers to the above chlorinated
vinyl chloride resin (100 parts). Furthermore, mercapto-octyltin (2
parts) as a stabilizer, two polyethylene waxes (Trade names
"AC-617A" and "AC-629A" manufactured by Allied Signal) (each 1
part) as lubricants, and titanium dioxide having a zinc content of
less than 0.01% (5 parts) as a filler were added. Then, the mixture
was blended with a homogenizer at 10,000 rpm for 4 minutes, and a
homogeneous composition was obtained.
[0031] The blend composition was subjected to a thermal stability
test using a laboplastomill (manufactured by TOYO SEIKI) at
190.degree. C. and 50 rpm with a loading amount of 65 g. A time, at
which a torque started to increase after the rotation was started
and then a torque became constant, was recorded as a
decomposition-starting time. The decomposition-starting time of
this composition was 13 minutes. The constant torque was 4.5
kg.cm.
Example 2
[0032] A chlorinated vinyl chloride resin composition was prepared
in the same manner as in Example 1 except that 3 parts of titanium
dioxide having a zinc content of less than 0.01% was added. Then,
the obtained blend composition was subjected to the same thermal
stability test as that in Example 1. The constant torque was 4.5
kg.cm, and the decomposition-starting time of this composition was
13 minutes.
Example 3
[0033] A chlorinated vinyl chloride resin composition was prepared
in the same manner as in Example 1 except that 1 part of titanium
dioxide having a zinc content of less than 0.01% was added. Then,
the obtained blend composition was subjected to the same thermal
stability test as that in Example 1. The constant torque was 4.5
kg.cm, and the decomposition-starting time of this composition was
13 minutes.
Comparative Example 1
[0034] A chlorinated vinyl chloride resin composition was prepared
in the same manner as in Example 1 except that 5 parts of titanium
dioxide having a zinc content of 0.30% was added. Then, the
obtained blend composition was subjected to the same thermal
stability test as that in Example 1. The constant torque was 4.5
kg.cm, and the decomposition-starting time of this composition was
5.5 minutes.
Comparative Example 2
[0035] A chlorinated vinyl chloride resin composition was prepared
in the same manner as in Example 1 except that 3 parts of titaniam
dioxide having a zinc content of 0.30% was added. Then, the
obtained blend composition was subjected to the same thermal
stability test as that in Example 1. The constant torque was 4.5
kg.cm, and the decoinposition-starting time of this composition was
6.0 minutes.
Comparative Example 3
[0036] A chlorinated vinyl chloride resin composition was prepared
in the same manner as in Example 1 except that 1 part of titanium
dioxide having a zinc content of 0.30% was added. Then, the
obtained blend composition was subjected to the same thermal
stabilIty test as that in Example 1. The constant torque was 4.5
kg.cm, and the decortposition-starting time of this composition was
7.0 minutes.
Example 4
[0037] A vinyl chloride resin having a polymerization degree of
1,000 was post-chlorinated to obtain a chlorinated vinyl chloride
resin having a chlorination degree of 67%.
[0038] MBS (Trade name "B561" manufactured by KANEKA CORPORATION)
(6 parts), and a chlorinated polyethylene having a chlorination
degree of 35% (Trade name "H135" manufactured by DAISO CO., LTD.)
(3 parts) were added as impact modifiers to the above chlorinated
vinyl chloride resin (100 parts). Furthermore, mercaptooctyltin (2
parts) as a stabilizer, two polyethylene waxes (Trade names
"AC-617A" and "PAC-629A" manufactured by Allied Signal) (each 1
part) as lubricants, and titanium dioxide having a zinc content of
less than 0.01% (5 parts) as a filler were added. Then, the mixture
was blended with a 300 liter super mixer while the temperature rose
to 130.degree. C., and a homogeneous composition was obtained.
[0039] The composition was extruded with a TEC conical extruder
(manufactured by Toshiba) in the form of a pipe. In the extrusion,
a resin temperature at the die tip was 194.6.degree. C.
[0040] The Charpy impact strength of this pipe was measured at
23.degree. C. and 0.degree. C. according to JIS K-7111. The impact
strength was 31 kg.cm/cm.sup.2 at 23.degree. C., and 21
kg.cm/cm.sup.2 at 0.degree. C.
[0041] A Vicat softening point was measured under a load of 5 kg
according to JIS K-7206. The softening point was 113.4.degree.
C.
[0042] The color tone of the pipe had no redness (AA) by the visual
inspection. Thus, the pipe was regarded as having good thermal
stability.
Example 5
[0043] A chlorinated vinyl chloride resin composition was prepared
in the same manner as in Example 4 except that 1 part of titanium
dioxide having a zinc content of less than 0.01% was added, and
then extruded in the form of a pipe by the same method as in
Example 4. A resin temperature at the die tip was 194.6.degree.
C.
[0044] The Charpy impact strength of this pipe measured according
to JIS K-7111 was 30 kg.cm/cm.sup.2 at 23.degree. C., and 20
kg.cm/cm.sup.2 at 0.degree. C.
[0045] The Vicat softening point of this pipe measured under a load
of 5 kg according to JIS K-7206 was 113.4.degree. C.
[0046] The color tone of the pipe had little redness (A) by the
visual inspection. Thus, the pipe was regarded as having good
thermal stability.
Example 6
[0047] A chlorinated vinyl chloride resin composition was prepared
in the same manner as in Example 4 except that 8 parts of MBS
(Trade name "B22" manufactured by KANEKA CORPORATION) was added as
an impact modifier, and the amount of the lubricant AC-617A was
changed to 1.3 parts, and then extruded in the form of a pipe by
the same method as in Example 4. A resin temperature at the die tip
was 193.6.degree. C.
[0048] The Charpy impact strength of this pipe measured according
to JIS K-7111 was 32 kg.cm/cm.sup.2 at 23.degree. C., and 22
kg.cm/cm.sup.2 at 0.degree. C.
[0049] The Vicat softening point of this pipe measured under a load
of 5 kg according to JIS K-7206 was 114.3.degree. C.
[0050] The color tone of the pipe had no redness (AA) by the visual
inspection. Thus, the pipe was regarded as having good thermal
stability.
Comparative Example 4
[0051] A chlorinated vinyl chloride resin composition was prepared
in the same manner as in Example 4 except that 5 parts of titanium
dioxide having a zinc content of 0.30% was added, and then extruded
in the form of a pipe by the same method as in Example 4. A resin
temperature at the die tip was 194.6.degree. C.
[0052] The Charpy impact strength of this pipe measured according
to JIS K-7111 was 31 kg.cm/cm.sup.2 at 23.degree. C., and 21
kg.cm/cm.sup.2 at 0.degree. C.
[0053] The Vicat softening point of this pipe measured under a load
of 5 kg according to JIS X-7206 was 113.4.degree. C.
[0054] The color tone of the pipe had redness (B) by the visual
inspection. Thus, the pipe was regarded as having low thermal
stability.
[0055] The above results are summarized in Tables 1 and 2.
1 TABLE 1 Ex. 1 Ex. 2 Ex. 3 C.E. 1 C.E. 2 C.E. 3 Chlorinated 100
100 100 100 100 100 vinyl chloride resin Impact modifier MBS 6 6 6
6 6 6 CPE 3 3 3 3 3 3 Stabilizer: 2 2 2 2 2 2 Mercaptooctyltin
Lubricant: 2 2 2 2 2 2 Polyethylene waxes Filler: TiO.sub.2 Zinc:
0.3% 5 3 1 Zinc: <0.01% 5 3 1 Plastomill properties Thermal
stability 13 13 13 5.5 6 7 (min.) Processability 4.5 4.5 4.5 4.5
4.5 4.5 (constant torque) (kg .multidot. cm)
[0056]
2 TABLE 2 Ex. 4 Ex. 5 Ex. 6 C.E. 4 Chlorinated 100 100 100 100
vinyl chloride resin Impact modifier MBS(B561) 6 6 6 MBS (B22) 8
CPE 3 3 3 Stabilizer: Mercaptooctyltin 2 2 2 2 Lubricant:
Polyethylene waxes 2 2 2.3 2 Filler: TiO.sub.2 Zinc: 0.3% 5 Zinc:
<0.01% 5 1 5 Properties of pipe Charpy impact strength (kg
.multidot. m/cm.sup.2) at 23.degree. C. 31 30 32 31 at 0.degree. C.
21 20 22 21 Vicat softening point (.degree. C.) (5 kg) 113.4 113.4
114.3 113.4 Color tone AA A AA B
* * * * *