JPH0362804A - Preparation of low molecular weight polyolefin - Google Patents

Abstract

PURPOSE:To contrive to stabilize the qualities of a low molecular polyolefin, such as color tone, by adjusting a thermal degradation temperature, the inner diameter of a tubular reactor, etc., within specific ranges when a polyolefin is thermally degradated in the tubular reactor in an inert gas to continuously prepare the low molecular polyolefin. CONSTITUTION:A polyolefin is charged to a tubular reactor 1 and 2 immersed in a salt bath 6 equipped with a stirrer 7 and subsequently degradated under a condition satisfied with an equation ((d) is the density (g/cm<3>) of the polyolefin at 23 deg.C; delta is the degradation amount (kg/hr) of the polyolefin per unit time; D is the inner diameter (m) of the tubular reactor; L is the length (m) of the tubular reactor; T is a degradation temperature ( deg.C)) at 300-459 deg.C for 0.5-10hr while an inert gas is blown in from a blowing opening 4, thereby providing a low molecular polyolefin having a number-average mol.wt. of 500-10000, preferably a hue of <=500 Hazen, a softening point of 90-210 deg.C, a melting viscosity of 20-100000cps at 140-160 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing low-molecular polyolefins. More specifically, the present invention relates to a method for producing industrially useful low-molecular polyolefins.

[Prior Art] Conventionally, a method of heating a polyolefin at 250 to 600° C. in an inert gas is known as a method of thermally decomposing a polyolefin to produce a low-molecular-weight polyolefin (for example, British Patent No. 5FI9043, U.S. Pat. Patent No. 2835
Ei No. 59, Japanese Patent Publication No. 3 Ei-8737, and Japanese Patent Publication No. 43-93H).

[Problem to be solved by the invention] However, with conventional technology, various qualities such as hue (
However, it has not been satisfactory in terms of industrial production of products that are stable in terms of odor (for example, odor, etc.).

[Means for Solving the Problems] The present inventors have arrived at the present invention as a result of intensive studies aimed at industrially producing low-molecular polyolefins with stable various qualities including hue.

That is, the present invention thermally degrades polyolefin in a tubular reactor in an inert gas to obtain a number average molecular weight of 500 to 10.00.
0 (hereinafter referred to as the above method in this section), heat degradation is carried out at 300 to 450°C for 0.5 to 10 hours and the formula [where d: 23 of the polyolefin] Density in °C (g/cm3), σ: Degradation ffi per unit time of polyolefin (kg/hr), D: Internal diameter of the tubular reactor (m), L: Length of the tubular reactor (m), T: Indicates degradation temperature (°C).

A method for producing a low-molecular-weight polyolefin, characterized in that it is carried out under conditions that satisfy the following conditions: In the above method, two or more tubes with different inner diameters are connected in series as a tubular reactor,
A method for producing a low molecular weight polyolefin, characterized in that the process is carried out at 50°C for 0.5 to 10 hours; in the above method, the tubes having different inner diameters are composed of a front tube and a final tube satisfying formulas (2) to (5). The manufacturing method according to claim 2 0.2≦DI/De≦o,s (2
)150≦Ll/DI≦1500
(3) 200≦Le/De≦soo
(4) 0.3≦LIX De/LeX DI≦4.
o (5) [where Dl: front tube inner diameter, De
: Indicates the internal diameter of the Q-way pipe, LJ: the pipe length of the front pipe, and Le: the pipe length of the final pipe. ]; In the above method, the pipe length is 5 to 2.
Using a 00m tubular reactor, 0.2 to 200kg/
The polyolefin was introduced into the tubular reactor at a temperature of 300-450°C under a pressure of cm3 and a linear velocity of 5-100 m/hr.
．． A method for producing a low molecular weight polyolefin, characterized in that the process is carried out for 5 to 10 hours; in the above method, a static mixer is used as part or all of the tubular reactor, and the process is carried out at 300 to 450°C for 0.5 to 10 hours. A method for producing low-molecular-weight polyolefins characterized by
/cm3), σ: Degradation amount of polyolefin per unit time (kg/hr), D: Inner diameter of tubular reactor (m),
L: length of the tubular reactor (m), D: decomposition temperature ('C).

The method according to claim 5, characterized in that the process is carried out under conditions that satisfy
A method for producing a low-molecular polyolefin, characterized in that the process is carried out for 10 to 10 hours; a method for producing a low-molecular polyolefin having a number average molecular weight of 500 to 10,000 by thermally degrading a polyolefin in an inert gas;
A method for producing a low molecular weight polyolefin, characterized in that the process is carried out at 300 to 450'C for 0.5 to 10 hours in the presence of 0.01 to 0.2 parts by weight of a phenolic antioxidant per 0 part by weight; and claims. This is a method for producing a low-molecular polyolefin by combining two or more of the methods described in any one of 1 to 8.

In the present invention, the polyolefin is a homopolymer of α-olefin selected from the group consisting of ethylene, propylene, l-butene, and 4-methyl-1-hentene, a copolymer of two or more of these α-olefins, or a copolymer of two or more of these α-olefins. Examples include copolymers of one or more α-olefins and one or more other α-olefins and/or vinyl compounds. Other α-olefins include olefins having 5 to 18 carbon atoms, such as 1-pentene,
Examples include 1-hexene, ■-octene, ■-decene, and ■-dodecene. Examples of vinyl compounds include unsaturated carboxylic acids or their anhydrides [(meth)acrylic acid, maleic anhydride, etc., and alkyl (meth)acrylates (the alkyl group is a group selected from the group consisting of methyl, ethyl, and butyl). etc.).

The melt flow rate of the polyolefin is usually 0.5 to 200 (g/l0ml), preferably 1 to 1100 (/l0ml). The number average molecular weight is usually 12,000 to 100,000, preferably 15.0
00 to 70,000.

The density of polyolefin at 23°C is usually 0.85~
I (g/am3).

An example of the manufacturing method of the present invention will be explained with reference to the drawings.

In Fig. 1, 1 is the front pipe of the tubular reactor, 2 is the final pipe,
3 is a gas-liquid separator, 4 is an inert gas inlet, 5 is a heat medium (salt bath) container, 6 is a salt bath, and 7 is a stirrer for the salt bath.

After the polyolefin is heated and degraded in a tubular reactor, volatile gaseous substances are removed in a gas-liquid separator to produce a low-molecular-weight polyolefin.

The inner diameter (D) of the tubular reactor is usually 10 to 300 mm.
1 preferably 20 to 200 mm. Length (L)
is usually 5 to 20011, preferably IO to 15
It is 0m.

If the length of the tubular reactor is less than 5 m, the odor of the obtained low molecular weight polyolefin increases and it is difficult to obtain a homogeneous product. 2
If the distance exceeds 00 m, the hue will deteriorate.

The length-to-inner diameter ratio (L,/D) of the tubular reactor is usually 50 to 20,001, preferably 120 to 15.
It is 00.

Tubular reactors are usually two or more stages of tubular reactors with different inner diameters,
Preferably, two or more, particularly preferably two stages connected in series are used. Even if the tubular reactor is straight,
Alternatively, it may be bent in a spiral shape.

The ratio of the inner diameter of the front tube (DI) to the inner diameter of the final tube (De) (
Di/De) is usually 0.2 to 0.8, preferably 0.3 to 0.7. When DI/De is less than 0.2, the hue of the obtained low-molecular polyolefin becomes poor,
If it exceeds 0.8, the odor will increase.

The ratio of the length of the front tube (Ll) to DI (Ll/DI) is usually from 150 to 1500, preferably from 200 to 12
Set it to 00. When Ll/DI is less than 150, the odor of the obtained low-molecular polyolefin becomes large, and when it exceeds 1500, the hue becomes poor.

The ratio of the final tube length (Le) to De (Le/De) is usually 200 to 800, preferably 250 to 700. When Le/De is less than 200, the odor of the obtained low-molecular polyolefin becomes large, and when it exceeds 800, the hue becomes poor.

The ratio between Ll/DI and Le/Da [(L1×De)/
(LeXDl) is usually 0.3 to 4.0, preferably 0.5 to 3.5. (L1×De) / (L
If eXDl) is less than 0.3, the obtained low-molecular polyolefin will have a poor hue, and if it exceeds 4.0, the odor will increase.

When the tubular reactor is composed of three or more stages, the inner diameter of the intermediate tube (the tube from the second stage to one stage before the final stage) is not particularly limited, but it is preferable to gradually increase the inner diameter. The length may be set arbitrarily.

In the present invention, a static mixer can be used as part or all of the tubular reactor.

A typical static mixer, such as a "static mixer" (Nikkan Kogyo Shimbun, September 30, 1980)
Examples include those listed on pages 5 and 6 of the Japanese publication). Using a static mixer 11 has the advantage of reducing odor.

The ratio of the length (L) to the inner diameter (D: expressed as the inner diameter of the passage pipe) of the static mixer is usually 50 to 2000,
Preferably it is 120 to +500.

Static mixers can be used in part or all of the tubular reactor. If a part is used, a normal pipe can be used for the rest.

In addition, when the static mixer is used in a portion, the position of the static mixer is not particularly limited. That is, it may be the first half, the second half, or the middle of the tubular reactor, but the first half is preferable. It may be used at one location or at two or more locations.

In the production method of the present invention, it is preferable to use a salt bath as the heat medium bath. The type of salt is lithium chloride.
Examples include mixed salts such as potassium chloride, lithium sulfate-potassium sulfate, sodium nitrate-potassium nitrate, sodium nitrite-potassium nitrate, and sodium hydroxide-potassium hydroxide.

Among these, a mixed salt of sodium nitrite and potassium nitrate is preferred.

12 The weight ratio when mixing salt is not particularly limited, but
Preferably, the mixed salt is selected so that the melting point range is from 50 to 200°C.

Heating is usually done using an electric heater. Temperature adjustment is not particularly limited, but preferably within a control range of ±0.degree. 2.degree. C. or less. Outside this range, it is difficult to obtain a homogeneous polyolefin.

The reaction in the present invention is usually carried out in an inert gas. Inert gases include argon, nitrogen, carbon dioxide and water vapor. Nitrogen is preferred. The flow rate is usually 5
to 1001/min.

A catalyst can also be used for the purpose of promoting the reaction. As a catalyst, a radical generating catalyst [benzoyl peroxide,
Peroxides such as di-tert-butyl peroxide and dicumyl peroxide; 2,2'-azobis(imbutyronitrile), 2,2'-azobis(2,
Azonitriles such as 4-dimethylvaleronitrile) and 4,4'-azobis(4-cyanovaleric acid)] and cracking catalysts (silica-alumina, silica-magnesia, activated clay, etc.).

The amount of the catalyst used is usually 0.1 to 20 parts by weight, preferably 1 to 10 parts by weight, per 100 parts by weight of the polyolefin. Addition of catalyst to the polyolefin is usually carried out before entering the tubular reactor.

The reaction temperature is 300 to 450°C, preferably 320 to 43°C.
It is 0°C. If the reaction temperature is less than 300° C., the reaction takes a long time (usually 30 hours or more), and the hue of the obtained low-molecular polyolefin deteriorates. When the temperature exceeds 450°C, the odor increases.

The reaction time is 0.5 to 10 hours, preferably 1 to 7 hours. If the reaction time is less than 0.5 hours, the odor of the obtained low-molecular-weight polyolefin will increase, and it will be difficult to obtain a homogeneous product. If it exceeds 10 hours, the hue will deteriorate.

The amount of polyolefin degraded per unit time is usually IO to 700 kgl, preferably 50 to 500 kg.
It is.

The pressure is usually 0.1 to 200 kg/am2, preferably 0.5 to 150 kg/cm2. Pressure is 0.
If it is less than 2 kg/Cm', the hue of the obtained low-molecular polyolefin becomes poor, and if it exceeds 200 kg/Cm', the odor increases.

In the present invention, the formula [where d: density of polyolefin at 23°C (g
/Cl113), σ: Density of polyolefin at 23°C (g/cm3), σ: Inner diameter of tubular reactor (m), L
: Length of tubular reactor (m), T: Degradation temperature ('C)
shows.

] Thermal degradation is performed to satisfy the following. Preferably -L Let's do it.

-L The hue of the lyolefin worsens, and when it exceeds 100, the odor increases.

If a static mixer is used partially or completely as a tubular reactor, the thermal degradation is determined by the formula [where dlσ, D ,
T and L are the same as in formula (1). The test shall be carried out under conditions that satisfy the following. Preferably it is carried out under -L.

If d·σ·D

When the tubular reactor has two or more stages, the inner diameter (D) and length (L) of the tube are calculated using the following formula.

L = L1+L2+ −−−−−−−−−−−−
---+Le [wherein, Ll, L2 -------
: The length of the -th stage, second stage, ... -th stage pipe, respectively.
Le: Length of final stage tube, DI, D2 -------
--: indicates the inner diameter of the tube at the -th stage, the second stage, the first stage, and so on, respectively; De: indicates the inner diameter of the pipe at the final stage. 16 If the tubular reactor is a static mixer, the inner diameter of the tube (
D) indicates the inner diameter of the passage tube of the static mixer, and the length is indicated by the length of the static mixer.

In the present invention, the flow linear velocity of the polyolefin is usually 0.
5 to 100 m/hrN preferably I to 80
m/hr. If the linear velocity is less than 0.5 m/hr, the hue of the obtained low-molecular polyolefin will deteriorate;
/hr, the odor increases.

In the present invention, thermal degradation is usually carried out by adding a phenolic antioxidant.

As the phenolic antioxidant, hindered phenol compounds are preferred. Examples of hindered phenol compounds include monocyclic hindered phenols such as 2,6-tert-butyl-4-methylphenol (B, H,
T), 2-tert-butyl-4-methylphenol (B, H, A), B-tert-butyl-2,4-methylphenol (24M [iB), 2,6-tert
t-Butylphenol (2[iB), 2-tert-butyl-4-ethylphenol (24M[iB), 2.6
-tert-butyl-4-ethylphenol, n-
Octadecyl-3-(4'-hydroxy-3,5-di-tert-butylphenyl)propionate, Dioctadecyl-4-hydroxy-3,5-di-tert-butylbenzyl phosphonate, Diethyl-4-hydroxy-3,5 -di-tBt-butylbenzylphosphonate and 6-(4oxy-3,5-di-tert-butylanilino)2,4-bis(n-octylthio)-
1,3,5-)-Ryazine; Bicyclic hindered phenols, such as 4,4'-thiobis(B-tert-butyl-3-methylphenol), 4,4'-butylidenebis([1-tert- butyl-3-methylphenol), 4,4'-methylenebis(6-tert-butylphenol), 4,4'-bis(2,6-tert-
butylphenol), 4,4'-thiobis(G-ter
t-butyl-0-cresol), 2,2'-methylenebis(4-methyl-[1-tert-butylphenol)
, 2,2'-thiobis(6-tertbutyl-4-methylphenol) and l,6-bis(3,5-di-te
rt-butyl-4-hydroxy-2-methylphenyl)
butane; and polycyclic (two or more rings) hindered phenols, such as 1,1,3-)lis(5-tert-butyl-4-hydroxy-2-methylphenyl)butane, 2
．． 4,1li-tris(3,5-di-tert-butyl-4-hydroxybenzyl)mesitylene, 1,3.5-
Tris(3,5-di-tert-phthyl-4-hydroxybenzyl)mesitylene, 1.3.5-1-lis(3,
5-tert-butyl-4-hydroxybenzyl)
Examples include incyanurate and tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxymethylcomethane.

Among these, 2,6-tert-butyl-4-methylphenol, 2-tert-butyl-4-methylphenol, n-octadecyl-3-(4'-hydroxy-3°5-di-tert-butylphenyl ) propionate, and tetrakis [β-(3,5-di-t
A particularly preferred ert-butyl-4-hydroxyphenyl)propionyloxymethylcomethane is tetrakis[β(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxymethylcomethane.

The amount of the phenolic antioxidant added is usually 0.01 to 0.2 parts by weight, preferably 0.02 to 0.15 parts by weight, per 100 parts by weight of the polyolefin.

19 If it is less than 0.01 part by weight, the hue of the obtained low-molecular polyolefin will deteriorate, and if it exceeds 0.2 part by weight, the odor will increase.

The method of adding the phenolic antioxidant is not particularly limited. For example, it may be added before thermal degradation or during thermal degradation.

The low molecular weight polyolefin obtained in this way is usually
It is formed into powder or pellets after a purification process to remove extremely low molecular weight substances. The purification and molding methods are not particularly limited and may be any conventional method.

The low molecular weight polyolefin obtained by the present invention usually has 5
It has a number average molecular weight of 00 to 10,000.

The hue is usually less than 500 on the Hazen scale, the softening point is 90 to 210°C, and the melt viscosity is 2 at 140°C or 160°C.
0 to 100,000 cps.

[Examples] The present invention will be further described below with reference to Examples, but the present invention is not limited thereto. Parts in the examples are parts by weight.

0 Example 1 High-pressure polyethylene with a density of 0.920 at 23°C and a melt flow rate of 2.0 (g/10 mIn) was placed in a salt bath (sodium nitrite-potassium nitrate solution) whose temperature was controlled at 410±0°1°C. A tubular reactor consisting of a front tube with an internal diameter of 49.5 mm and a length of GOm and a rear tube with an internal diameter of 97.1 mm and a length of 50 m, immersed in a mixed salt (45:55 by weight), was supplied with nitrogen at +51/min. While being introduced, it was passed through at a flow rate of 180 kg/hr for continuous thermal degradation. The obtained low-molecular-weight polyethylene was a colorless wax having a number average molecular weight of 2200, a hue (Hazen) of 60, a softening point of +09°C, and a melt viscosity of 350 cps at 140°C.

Example 2 The same procedure as in Example 1 was carried out except that low-pressure polyethylene having a density at 23°C of 0.957 and a melt flow rate of 12.2 (g/lomin) was used. The obtained low molecular weight polyethylene had a number average molecular weight of 4200. Hue (Hazen) 501 It was a colorless wax with almost no odor and a melt viscosity of 3300 cps at softening points of 127°C and 140°C0 Example 3 Salt bath similar to Example 1 with temperature controlled at 395 ± 0.1°C The inner diameter is 73.9 mm and the length is 100 m.
The high-pressure polyethylene used in Example 1 was heated continuously for 10 minutes under a pressure of 50 kg/cm3 and at a linear velocity of 45 m/hr while nitrogen was introduced at a rate of 101/river into a tubular reactor. It has declined. The obtained low molecular weight polyethylene had a number average molecular weight of 33,001 and a hue (Hazen) of 30.
Softening point III °C and melt viscosity at 140 °C 880
It was a CPS colorless wax with almost no odor.

Example 4 23 instead of the high pressure polyethylene used in Example 3
Density at °C is 0.900 and melt flow rate is 8
．． The same procedure as in Example 3 was carried out except that 0 (g/10 mIn) polypropylene was used. The obtained low molecular weight polyethylene had a number average molecular weight of 3000 and a hue (Hazen) of 100.
It was a slightly yellow wax with almost no odor and a softening point of 147° C. and a melt viscosity of 100 cps at I[iooC.

Example 5 The same procedure as in Example 1 was carried out except that the front tube of the tubular reactor used in Example 1 was replaced with a fixed-blade static mixer. The obtained low molecular weight polyethylene has a number average molecular ffl
2400, Hue (Hazen) 501 Softening point 109℃
It was a colorless, completely odorless wax with a melt viscosity of 390 cps at +40°C.

Example 6 In Example 2, 2- was added as an antioxidant before passing through the tubular reactor.
tert-butyl-4-methoxyphenol 0.05%
The same procedure as in Example 2 was carried out except that the following was added to the polyethylene. The obtained low molecular weight polyethylene had a number average molecular weight of 440.
0, hue (Hazen) 20, softening point 128℃ and 14
It was a colorless wax with a melt viscosity of 3400 cps at 0°C and almost no odor.

[Effects of the Invention] By the production method of the present invention, it is possible to industrially produce stable low-molecular polyolefins of various hues and of various qualities. Specifically, 1. A low-molecular polyolefin with good hue can be obtained.

3 2. A low-molecular-weight polyolefin with little odor can be obtained.

3. A low-molecular polyolefin with good thermal stability can be obtained.

4. Industrial-scale production of low-molecular-weight polyolefins by thermal degradation can be efficiently performed.

Due to the above-mentioned effects, the low-molecular-weight polyolefin obtained by the present invention can be suitably used as a pigment dispersant for plastics, a processability improver for plastics, a rubber additive, a compounding agent for ink and paint, a release agent for toner, etc. .

[Brief explanation of drawings]

FIG. 1 is a flowchart showing an embodiment of the present invention. 1 and 2: tubular reactor 6: Salt bath 24 hand Continued Supplementary Positive book

Claims (1)

[Claims] 1. A method for continuously producing a low molecular weight polyolefin having a number average molecular weight of 500 to 10,000 by thermally degrading a polyolefin in an inert gas in a tubular reactor, wherein the thermal degradation is 300%. ~450°C for 0.5 to 10 hours and formula 0.
3≦(d・σ・D)/(T・L)×10^4≦100(
1) [where d: density of polyolefin at 23°C (g
/cm^3), σ: Degradation amount of polyolefin per unit time (kg/hr), D: Inner diameter of tubular reactor (m), L
: Length of tubular reactor (m), T: Degradation temperature (°C). A method for producing a low-molecular polyolefin, characterized in that it is carried out under conditions that satisfy the following. 2. In a method of continuously producing low-molecular polyolefin with a number average molecular weight of 500 to 10,000 by thermally degrading polyolefin in an inert gas in a tubular reactor, two stages of tubes with different inner diameters are used as the tubular reactor. 30 or more connected in series
A method for producing a low-molecular polyolefin, characterized by carrying out thermal degradation at 0 to 450°C for 0.5 to 10 hours. 3. A first-stage reactor (hereinafter referred to as front tube) and a final-stage reactor (hereinafter referred to as front tube) whose tubes have different inner diameters satisfy formulas (2) to (5).
3. The manufacturing method according to claim 2, comprising: a final tube). 0.2≦D1/De≦0.8 (2) 150≦L1/D1≦1500 (3) 200≦Le/De≦800 (4) 0.3≦(L1×De)/(Le×D1)≦ 4.0 (5
) [where, D1: front tube inner diameter, De: final tube inner diameter, L1
: indicates the length of the front tube, Le: indicates the length of the final tube. ] 4. A method for continuously producing a low molecular weight polyolefin having a number average molecular weight of 500 to 10,000 by thermally degrading polyolefin in an inert gas in a tubular reactor, the tube length being 5 to 2.
Using a 00m tubular reactor, 0.2 to 200kg/
The polyolefin was introduced into the tubular reactor at a temperature of 300-450°C under a pressure of cm^3 and a linear velocity of 5-100 m/hr.
．． A method for producing a low-molecular polyolefin, characterized by carrying out thermal degradation for 5 to 10 hours. 5. Polyolefin in a tubular reactor in an inert gas for 30
In a method of continuously producing a low molecular weight polyolefin having a number average molecular weight of 500 to 10,000 by thermal degradation at 0 to 450°C for 0.5 to 10 hours, a static mixer is used as part or all of the tubular reactor. , 300-4
A method for producing a low-molecular polyolefin, characterized by carrying out thermal degradation at 50° C. for 0.5 to 10 hours. 6. Thermal degradation is expressed by the formula 0.3≦(d・σ・D)/(T・L)×10^4≦50
0(1)' [where d: density of polyolefin at 23°C (g/cm^3), σ: amount of degradation of polyolefin per unit time (kg/hr), D: inner diameter of tubular reactor (m
), L: length of tubular reactor (m), T: degradation temperature (℃)
shows. 6. The manufacturing method according to claim 5, wherein the manufacturing method is carried out under conditions that satisfy the following conditions. 7. In a method for continuously producing a low molecular weight polyolefin with a number average molecular weight of 500 to 10,000 by thermally degrading a polyolefin in an inert gas in a tubular reactor, the tubular reactor is placed in a bath consisting of an inorganic salt mixture. Soak for 300-450 yen
A method for producing a low-molecular-weight polyolefin, characterized by carrying out thermal degradation at ℃ for 0.5 to 10 hours. 8. In a method for continuously producing a low molecular weight polyolefin having a number average molecular weight of 500 to 10,000 by thermally degrading a polyolefin in an inert gas, polyolefin 100
Phenolic antioxidant 0.01 to 0 per part by weight
．． 0.5 to 1 at 300 to 450°C in the presence of 2 parts by weight
A method for producing a low-molecular polyolefin, which comprises performing thermal degradation for 0 hours. 9. A method for producing a low-molecular polyolefin by combining two or more of the methods according to any one of claims 1 to 8.