JPH04331233A - Polysiloxane/polylactone block copolymer and its production - Google Patents

Abstract

PURPOSE:To obtain easily the title star copolymer of a controlled chain length by effecting the ring-opening polymerization of hexamethylcyclotrisiloxane by using a specified initiator to form a bonding part at the end of each siloxane chain, and effecting the ring-opening polymerization of a lactone. CONSTITUTION:The title copolymer having siloxane blocks of formula III (wherein (x) is 5-100; and Mc is CH3) and polylactone segments of formula IV (wherein E is an end group, (b) is 3-5; and (n) is 1-200) each bonded to the end of each siloxane chain through a bonding part of formula I or II (wherein (a) is as defined below) is obtained by effecting the ring-opening polymerization of hexamethylcyclotrisiloxane by using 1,3,5-benzenetris(lithium dimethylsilanolate) as an initiator to form a bonding part of formula I or II (wherein (a) is 3-5; and Si is bonded to the siloxane chain) at the end of each siloxane chain and effecting the ring-opening polymerization of a lactone. This copolymer is useful as, e.g. a medical polymeric material.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a polysiloxane comprising a star polymer type polysiloxane block having a benzene ring as a central core and a polylactone block bonded to the tip of a siloxane chain via a bonding part. -Relating to polylactone block copolymers. Furthermore, the present invention relates to a method for producing such block copolymers.

0002

BACKGROUND OF THE INVENTION Block copolymers of polysiloxane blocks such as polydimethylsiloxane and polylactones such as polycaprolactone are known.

For example, JP-A-59-207922 and JP-A-61-66722 disclose linear polysiloxanes, particularly polydiorganosiloxanes having silicon functional groups such as silanol groups and silylamino groups at the molecular terminals. A linear block copolymer of terblock or polyblock obtained by polymerizing lactone at the terminal of siloxane is disclosed. Such a copolymer does not have sufficient hydrolysis resistance because the bond between polysiloxane and polylactone is a Si-O-C bond.

In order to increase the hydrolysis resistance of the bond between both segments, a carbon functional group is introduced into the terminal or side chain of polysiloxane, and lactone is polymerized using this as a starting point. Block copolymers and graft copolymers can be obtained. Polyester resins and polyurethane resins obtained by such methods are disclosed in JP-A No. 1-299819, JP-A No. 2-102096,
It is disclosed in Japanese Patent No. 2-228323. Further, a graft copolymer obtained by a similar method and having a polysiloxane as a backbone and a side chain consisting of a polyether part and a polylactone part is disclosed in JP-A-2-272021. A graft copolymer having a similar structure is also disclosed in Japanese Patent Publication No. 50-39648, although the production method is different.

However, such known polysiloxane-polylactone block or graft copolymers all have a polylactone segment at one or both ends of a linear or slightly branched polysiloxane segment. , a similar polysiloxane with a polylactone chain formed as a side chain. A polysiloxane star polymer in which a polylactone is formed at the tip of each siloxane chain as in the present invention has not been obtained to date.

[0006] In addition, all of the above conventional copolymers rely on reaction mechanisms that make it difficult to control molecular weight distribution.
As a biocompatible polymer, a molecular weight distribution sufficient for molecular design aimed at forming microdomains has not yet been obtained.

Furthermore, in the case of a block copolymer consisting of two or three chain blocks, the molecular size of the polymer having the required molecular weight becomes large, which imposes restrictions on the design of the microdomain structure.

Various types of star polymers or starburst polymers have been known that have an atom or atomic group as a central core and regularly have linear or branched chains on the outside. Voegtle et al. synthesized a star polymer in which molecular chains consisting of thioethylene units and oxyethylene units were formed from the six carbon atoms of a benzene ring as the core, and found that such a polymer had the ability to incorporate metal ions. I found (
F. Voegtle et al., Angew. Chem. Int
．． Ed. Engl. , vol. 13, p. 814 (1974)).

Furthermore, Tomalia et al. obtained a polyamidoamine-based starburst polymer with a dendritic branched molecular structure by repeating the Michael addition reaction of methyl acrylate and amination with ethylenediamine using ammonia as the core. (D.A. Tomil
ia et al., Angew. Chemie. Intern. E
d. Engl. , vol. 29, p. 138 (1990))
.

Regarding polysiloxanes, the present inventors have obtained various polysiloxane-based star polymers in which the silicon atom of methyltrichlorosilane is the central core. That is, a tetrasiloxane having a branched skeleton is obtained by a desalting reaction from methyltrichlorosilane and lithium phenyldimethylsilanolate, and this is treated with bromine to replace the phenyl group with a bromine atom, and then a dialkylamine such as diethylamine is prepared. and further reacted with phenyldimethylsilanol. This process can be repeated to extend three siloxane chains.

Further, in the process, branching can be caused by using a compound having a branched skeleton synthesized as follows in place of phenyldimethylsilanol. That is, trisiloxane is obtained by a desalination reaction from one molecule of methyltrichlorosilane and two molecules of sodium phenyldimethylsilanolate, and after hydrolyzing the remaining chlorine atom, one chlorine atom of dimethyldichlorosilane and (dimethylhydroxysiloxy)bis(phenyldimethylsiloxy)methylsilane is obtained by carrying out a dehydrochlorination reaction and then hydrolyzing the chlorine atom introduced by the above reaction. In this tetrasiloxane having a branched skeleton, one of its three silicon atoms is bonded to a hydroxyl group and the other two are bonded to a phenyl group, so this is reacted with the aminated siloxane mentioned above. By introducing a trisiloxane unit containing two phenyl groups at the end of the molecular chain, followed by bromination-defhenylation as described above, and further repeating the amination reaction, branching can be generated ( Morikawa et al., Proceedings of the Society of Polymer Science, Vol. 39, p. 308 (1990);
(See Morikawa et al., Fine Chemical, 1990, No. 17, p. 5).

0012

SUMMARY OF THE INVENTION An object of the present invention is to obtain a star polymer type polysiloxane/polylactone block copolymer which can be easily synthesized and whose molecular weight can be controlled.

Another object of the present invention is to provide an advantageous method for synthesizing the star polymer type polysiloxane-polylactone block copolymers.

[0014]

[Means for Solving the Problems] That is, the present invention provides the general formula

[0015]

[C7]

(where x represents a number from 5 to 100; M
e represents a methyl group) and the tip of the siloxane chain

[0017]

[Chemical formula 8]

[0018] or

[0019]

[Chemical formula 9]

(wherein a represents a number from 3 to 5; the silicon atom is bonded to the siloxane chain)

[0021]

[Chemical formula 10]

(In the formula, E represents a terminal group; b is 3 to 5
y represents a number from 1 to 200);
Also, a step of ring-opening polymerization of hexamethylcyclotrisiloxane (hereinafter referred to as D3) using 1,3,5-benzentris (lithium dimethylsilanolate) as an initiator;

[0023]

[Chemical formula 11]

or the formula

[0025]

[Chemical formula 12]

The above-mentioned polysiloxane-polylactone block copolymer is characterized by comprising a step of forming a bond represented by the formula (wherein a is as described above); and a step of anionic ring-opening polymerization of a lactone. This invention relates to a method for manufacturing a combination.

The polysiloxane/polylactone block copolymer of the present invention has a benzene ring as the central core, and the 1,
A polysiloxane segment represented by formula (I) in which three siloxane chains are formed from the 3,5-position carbon atoms, and a polylactone segment that is bonded to the terminal of the siloxane chain via a bonding part. It consists of

The polysiloxane chain is obtained by living anion ring-opening polymerization of D3 and does not involve an equilibration reaction, so the length of the siloxane chain is 3x + 1 silicon atoms (which are introduced in the bond forming reaction described later). 3x+2 including silicon atoms). x is the degree of polymerization of ring-opening polymerization,
5 to 100, preferably 10 per siloxane chain
~50. When x is less than 5, the polysiloxane properties are insufficient, and when x exceeds 100, synthesis becomes difficult and the uniformity of the siloxane chain length is impaired.

A join part is an expression (
It is the structure shown in II) or the structure shown in formula (III) which performs branching. a is selected from the range of 3-5. When a is less than 3, the structure shown in formula (II) in particular is chemically unstable and susceptible to hydrolysis. On the other hand, when a exceeds 5, it is difficult to synthesize. The silicon atom of the bond bonds to and forms one end of the siloxane chain.

The polylactone segment is bonded to the carbon atom of the bond described above and is represented by formula (IV). Formula (IV
), b represents a number from 3 to 5, preferably 5. y represents a number from 1 to 200, preferably from 3 to 50. Although the terminal group E is lithium at the time of polymerization, it can be changed to a hydrogen atom or an alkyl group by stopping the reaction with water, alcohol, or the like. Depending on the type of alcohol used, the alkyl group can be methyl,
Examples include ethyl, propyl, butyl, and methyl group is common.

The block copolymer of the present invention can be obtained as follows. First, 1,3,5-tris(dimethylhydroxysilyl)benzene is lithiated using a lithiation agent such as n-butyllithium.
Synthesize 3,5-benzentris(lithium dimethylsilanolate). Then, using this as an initiator, ring-opening polymerization of D3 is carried out as shown in the following formula.

[0032]

[Chemical formula 13]

(In the formula, x and Me are as described above.)

[0034] All of these reactions can be carried out, for example, at room temperature,
It can be carried out under normal pressure without a solvent or preferably in the presence of a solvent. As a solvent, diethyl ether,
Ether solvents such as diisopropyl ether, dibutyl ether, dioxane, and tetrahydrofuran; hydrocarbon solvents such as benzene, toluene, xylene, n-hexane, n-heptane, and cyclohexane; and mixtures thereof. D per mole of initiator
Any x siloxane chain can be formed by changing the number of moles of 3. As mentioned above, this reaction proceeds by the mechanism of living anionic polymerization, and a polysiloxane starpolymer is obtained in which the number of silicon atoms is 3x+1, the molecular chain length distribution is relatively uniform, and the terminal Z of the molecular chain is a lithium atom. . The molecular weight distribution of the star polymer is also narrow, with a molecular weight distribution coefficient (Mw/Mn) of 1.5 or less, and 1.5 when x is 20 or less.
It can be controlled to 3 or less.

The thus obtained polysiloxane type star polymer having a lithium atom at the end of the siloxane chain is reacted with a dimethylchlorosilane derivative or a dimethylmethoxysilane derivative having a corresponding carbon functional group to form a bonding portion. can be introduced. Examples of such silane derivatives used when the molecular chain is not branched at this part include 3-benzyloxypropyldimethylchlorosilane, 3-benzyloxybutyldimethylmethoxysilane, 4-benzyloxybutyldimethylchlorosilane, and 4-benzyloxybutyldimethylchlorosilane. -benzyloxybutyldimethylmethoxysilane and 5-benzyloxypentyldimethylchlorosilane. In addition, when branching the molecular chain at this part, 4,
Examples include 4-bis(benzyloxymethyl)butyldimethylchlorosilane. Generally, dimethylchlorosilane derivatives are preferred in terms of reactivity. Although the reaction proceeds at room temperature, the temperature may be raised to promote the reaction if necessary. In addition, although the reaction proceeds without a solvent, the above-mentioned D3
The reaction may be carried out in the presence of the same solvent used for the living anionic polymerization.

Next, the carbon functional group-containing star polymer in which Y or X is a benzyloxy group is converted into a hydroxyl group by a hydrogenation reaction. Hydrogenation can be carried out at room temperature using, for example, palladium supported on carbon as a catalyst.

[0037] Then, the terminal hydroxyl group of the bonding part is lithiated. That is, n-butyllithium is reacted. The reaction can be carried out, for example, at temperatures from -70°C to +50°C in the presence of a solvent. Examples of the solvent include those used in the synthesis of 1,3,5-benzentris(lithium dimethylsilanolate) described above.

Using the lithium compound thus obtained as an initiator, ring-opening polymerization of lactone is carried out. Examples of the lactone include γ-butyrolactone, δ-valerolactone, and ε-caprolactone, with ε-caprolactone being preferred. As in the case of D3, this ring-opening polymerization also proceeds by the mechanism of living anionic polymerization, so that polylactone segments with uniform molecular chain lengths are obtained. The end of the polylactone chain thus obtained is an active lithium atom. After the reaction is completed, it can be treated with water or alcohol to convert the terminal group into a hydrogen atom or an alkyl group depending on the treating agent. Examples of alcohol include methanol, ethanol, isopropanol, butyl alcohol, and the like.

[0039]

According to the present invention, a polysiloxane/polylactone block copolymer having a star polymer structure and a method for producing the same can be provided. In the block copolymer obtained by the present invention, both the siloxane chain and the polylactone chain are formed by living anionic polymerization, so that each chain length is uniform.

It is known that polydimethylsiloxane has excellent biocompatibility. When copolymerizing polylactone therewith, the star polymer of the present invention is more advantageous in molecular design than the chain polymer because the molecular size of the central polysiloxane segment can be made smaller.

The block copolymer of the present invention is useful as a medical polymer material.

[0042]

[Examples] The present invention will be explained below by referring to reference examples and examples. In these Reference Examples and Examples, parts represent parts by weight. Note that the present invention is not limited to these Examples.

Reference Example 1 Synthesis of 1,3,5-tris(dimethylhydroxysilyl)benzene 6.949 parts of Magnesium metal, 21.26 parts of dimethylchlorosilane and 1
Add 77 parts of tetrahydrofuran and add 25 parts of tetrahydrofuran while stirring.
1,3,5-tribromobenzene was added dropwise. After the addition was completed, stirring was continued overnight. After removing the remaining magnesium by filtration, tetrahydrofuran was distilled off, diethyl ether was added to perform extraction, diethyl ether was distilled off from the organic layer, and then by vacuum distillation,
Colorless and transparent liquid with a boiling point of 88°C/1 Torr9.143
I got the department.

Next, ethanol 6 was added to the same reaction vessel.
A liquid prepared by dissolving 2 parts of sodium in 0.1 part was charged, and a mixed solution of 7.11 parts of sodium hydroxide, 6.10 parts of water, and 34.4 parts of methanol was added thereto. The liquid material previously obtained by vacuum distillation was added dropwise to this. 3 more
After stirring for 0 minute, an aqueous solution of 63.14 parts of potassium dihydrogen phosphate was added and stirring was continued. After the reaction was completed, the mixture was extracted with diethyl ether, dehydrated with anhydrous magnesium sulfate, filtered, and the solvent was distilled off to obtain a solid reaction product. Recrystallization from benzene gave a white solid with a melting point of 168.5°C.

It was confirmed by NMR using a nuclear magnetic resonance apparatus JNM-FX900 (manufactured by JEOL Ltd.) that the obtained white solid was 1,3,5-tris(dimethylhydroxysilyl)benzene. 1H NMR (MDSO-d6) δ value (ppm
): 0.3 (s, 6H), 5.9 (s, 1H)7.
8 (s, 3H)

Example 1 Synthesis of lithium-terminated polysiloxane star polymer 1,3 synthesized in Reference Example 1 was placed in a reaction vessel equipped with a water cooling jacket, a stirrer, a thermometer, a dry nitrogen inlet, and a dropping device.
,5-tris(dimethylhydroxysilyl)benzene0
．． 1 part and 44.4 parts of dry tetrahydrofuran. After purging the system with dry nitrogen, while cooling the reaction vessel with water, 0.42 parts of an n-hexane solution containing 1.6N n-butyllithium was slowly added dropwise to react.
3,5-benzentris(lithium dimethylsilanolate) was obtained.

Next, a solution obtained by dissolving 6.28 parts of D3 in 17.8 parts of tetrahydrofuran was mixed with the solution of the lithium compound thus obtained. Ring-opening polymerization of D3 was performed by stirring this mixed solution at 20° C. for 3 hours.

[0048] An excess amount of trimethylchlorosilane was added dropwise to the solution of the lithium-terminated polysiloxane star polymer thus obtained to trimethylsilylate the terminals, and then the solvent and excess trimethylchlorosilane were distilled off to obtain the obtained lithium-terminated polysiloxane star polymer. Benzene was added to the resulting colorless and transparent oil, and the resulting product was purified by freeze-drying, and NMR confirmed that it was a trimethylsilyl-terminated star polymer. 1H NMR δ value (ppm): 0.1 (s,
333H), 7.3(s, 3H)

[0049] Regarding this oil, the number average molecular weight (Mn) and molecular weight distribution coefficient (Mw/Mn) were determined by comparing the GPC output curve monitored by RI with toluene as a solvent and a standard polystyrene sample. When Mn was determined by VPO, the following values were obtained. Note that x of each siloxane chain determined from the above blending ratio was 30, the theoretical amount of Mn was 20,500, and the measurement results supported this. GPC Mn: 22,500
Mw/Mn: 1.47VPO Mn: 18
,300

Reference Example 2 Synthesis of 3-benzyloxypropyldimethylchlorosilane In a reaction vessel equipped with a stirrer, a thermometer, and a dropping device with a drying tube, 17.4 parts of allyl alcohol, 7.2 parts of sodium hydride, and 177.6 parts of tetrahydrofuran was charged and stirred. When 51.3 parts of benzyl bromide was added dropwise to this, sodium bromide was observed to precipitate due to the reaction. This was filtered and then distilled under reduced pressure to obtain a colorless and transparent liquid with a boiling point of 95°C/20 Torr.
8.2 parts were obtained. The product was confirmed to be allyl benzyl ether by NMR.

Next, 357 parts of diethyl ether, 50.0 parts of dimethylchlorosilane and 0.0 parts of dimethylchlorosilane were added to this liquid.
Two parts of chloroplatinic acid were added and heated to the reflux temperature of diethyl ether with stirring. Diethyl ether was distilled off, and 49.9 parts of a transparent yellow liquid with a boiling point of 100° C./1 Torr was obtained by distillation under reduced pressure. NMR reveals that the product is 3-
It was confirmed that it was benzyloxypropylmethylchlorosilane. 1H NMR δ value (ppm): 0.3 (s, 6
H), 0.8 (t, 2H), 1.6 (m, 2H),
3.3 (t, 2H), 4.4 (s, 2H), 7.2
(s, 5H)

Example 2 Synthesis of 3-benzyloxypropyl-terminated polysiloxane star polymer While stirring a tetrahydrofuran solution containing 23.3 parts of the lithium-terminated polysiloxane star polymer synthesized in Example 1, 3-benzyloxypropyl-terminated polysiloxane star polymer was synthesized in Reference Example 2. - 3.0 parts of benzyloxypropyldimethylchlorosilane was added dropwise. After the dropwise addition was completed, stirring was continued for another 2 hours to complete the reaction, and then the solvent was removed under reduced pressure to obtain 23.6 parts of a product. NMR confirmed that the product was a 3-benzyloxypropyl-terminated polysiloxane. 1H NMR δ value (ppm): 0.3 (s, 3
33H), 0.8(t, 6H), 1.6(m, 6H
), 3.3 (t, 6H), 4.4 (s, 6H), 7
．． 2 (m, 15H), 7.3 (s, 6H)

Example 3 Synthesis of 3-hydroxypropyl-terminated polysiloxane star polymer 20.0 parts of the 3-benzyloxypropyl-terminated polysiloxane star polymer synthesized in Example 2 was dissolved in 237 parts of ethanol and placed in a reaction vessel. I prepared it. 0.1 part of palladium/activated carbon containing 10% by weight of palladium was added, hydrogen gas was filled, and the mixture was stirred at 20° C. for 8 hours to react. After the reaction is complete, filter the palladium/activated carbon,
The solvent was distilled off under reduced pressure to obtain 19.8 parts of product.

[0054] It was confirmed by NMR that the benzyloxy group was eliminated to form a hydroxyl group. 1H NMR δ value (ppm): 0.3 (s, 3
33H), 0.8(t, 6H), 1.6(m, 6H
), 3.3 (t, 6H), 3.8 (s, 6H), 7
．． 3 (s, 3H)

Reference Example 3 Synthesis of 4,4-bis(benzyloxymethyl)butyldimethylchlorosilane 5.7 parts of sodium and 158 parts of ethanol are heated in the presence of benzene, and the water produced is azeotropically distilled with benzene. After adding 40.0 parts of diethyl malonate to the ethanol solution of sodium ethoxide prepared by the removal method, 32.0 parts of allyl bromide was added dropwise. While stirring, the reaction solution was gradually warmed from 20°C and maintained at 80°C for 2 hours. The resulting precipitate was filtered, the solvent was distilled off under reduced pressure,
The residue was distilled under reduced pressure to a boiling point of 112-115℃/25T.
41.0 parts of monoallyl ethyl malonate of orr was obtained. The yield was 82% based on the theoretical amount. 1H NMR δ value (ppm): 1.2 (t, 6
H), 2.5 (t, 2H), 3.3 (m, 1H),
4.0 (q, 4H), 4.9 (m, 2H), 5.6
(m, 1H)

47.0 parts of lithium aluminum hydride was suspended in 444 parts of tetrahydrofuran, and while stirring, 41.0 parts of monoallyl ethyl malonate obtained as described above was added dropwise. After dropping, the mixture was refluxed at 65°C for 8 hours, then excess sodium sulfate was added to deactivate the lithium aluminum hydride, the precipitate was filtered, and the solvent was removed under reduced pressure.
The residue was distilled under reduced pressure to a boiling point of 83-86°C/0.5
18.2 parts of Torr residue were obtained. NMR confirmed that the product was 4,4-bis(hydroxymethyl)-1-butene. The yield was 79% based on the theoretical amount. 1H NMR δ value (ppm): 1.9 (m, 1
H), 3.5 (m, 4H), 4.0 (s, 2H),
4.9 (m, 2H), 5.7 (m, 1H)

0057
] 21.0 parts of 4,4-bis(hydroxymethyl)-1-butene obtained as above was dissolved in 88.8 parts of tetrahydrofuran, 10 parts of sodium hydride was added thereto, and then 65.0 parts of benzyl bromide was added dropwise while stirring. The reaction produced a precipitate of sodium bromide, which was filtered and the solvent was distilled off under reduced pressure.
Boiling point 170-178℃/0.5 Tor by vacuum distillation
32 parts of product r were obtained.

[0058] NMR confirmed that the product was 4,4-bis(benzyloxymethyl)-1-butene. The yield was 62% based on the theoretical amount. 1H NMR δ value (ppm): 2.0 (m, 3
H), 3.4 (d, 4H), 5.4 (s, 4H),
5.7 (m, 1H), 5.9 (m, 2H), 7.2
(m, 10H)

[0059] This product is then treated with 3
5.7 parts of diethyl ether, 12 parts of dimethylchlorosilane and 0.1 part of chloroplatinic acid were added, and the mixture was heated to the reflux temperature of diethyl ether for 2 hours with stirring to carry out a hydrosilylation reaction. After the reaction, diethyl ether was distilled off, and the boiling point was 180-185°C/0.5 by distillation under reduced pressure.
35 parts of a colorless and transparent liquid of Torr was obtained.

[0060] NMR revealed that the obtained liquid was 4,4-
It was confirmed that it was bis(benzyloxymethyl)butyldimethylchlorosilane. The yield is 83% based on the theoretical amount.
%Met. 1H NMR δ value (ppm): 0.3 (s, 6
H), 0.8 (m, 2H), 1.7 (m, 6H),
1.8 (m, 1H), 3.4 (d, 4H), 4.4
(s, 4H) 7.2 (m, 10H)

Example 4 Synthesis of 4-4-bis(benzyloxymethyl)butyl-terminated polysiloxane star polymer While stirring a tetrahydrofuran solution containing 23.3 parts of the lithium-terminated polysiloxane star polymer synthesized in Example 1, 4,4-bis(benzyloxymethyl)butyldimethylchlorosilane synthesized in Reference Example 3 4.5
part was dripped. After the dropwise addition was completed, filtration was performed, and the solvent was distilled off under reduced pressure to obtain a product of 23.6. NMR confirmed that the product was a 4,4-bis(benzyloxymethyl)butyl-terminated polysiloxane star polymer. 1H NMR δ value (ppm): 0.2 (s, 3
42H), 0.8(m, 6H), 1.7(m, 12H
), 1.8 (m, 3H), 3.4 (d, 12H) 4.
4 (s, 12H), 7.2 (m, 30H), 7.3 (s
,3H)

Example 5 Synthesis of 4,4-bis(hydroxymethyl)butyl-terminated polysiloxane star polymer Polysiloxane star polymer 20 synthesized in Example 4
．． 0 part was dissolved in 237 parts of ethanol and charged into a reaction vessel. Add 0.1 part of palladium/activated carbon containing 10% by weight of palladium, fill with hydrogen gas,
The mixture was stirred and reacted at ℃ for 8 hours. After the reaction is completed, the palladium/activated carbon is filtered, the solvent is distilled off under reduced pressure, and 19.
7 parts of product were obtained.

[0063] It was confirmed by NMR that the benzyloxy group was removed to form a hydroxyl group. 1H NMR δ value (ppm): 0.2 (s, 3
42H), 0.8(m, 6H), 1.7(m, 12H
), 1.8 (m, 3H), 3.4 (d, 12H), 3
．． 8 (s, 6H), 7.3 (s, 3H)

Example 6 3.68 parts of the 3-hydroxypropyl-terminated polysiloxane star polymer synthesized in Example 3 was dissolved in 43.3 parts of toluene, and n-butyllithium containing 1.6N was dissolved therein. 0.62 parts of hexane solution was added, and the mixture was stirred and reacted at room temperature to lithiate the terminals. 3.68 parts of ε-caprolactone was added to this solution and stirred at room temperature for 1 hour to perform ring-opening polymerization of ε-caprolactone. After the reaction, toluene was removed under reduced pressure, the residue was washed with water, and then dried under reduced pressure to obtain a transparent inorganic solid. The presence of dimethylsilyl group, dimethylene group, methyleneoxy group, methylenecarbonyl group, and benzene ring was confirmed by NMR. 1H NMR δ value (ppm): 0.1 (s, intensity ratio 1), 1.65 (m, 0.45), 2.35 (m
, intensity ratio 0.215), 4.1 (m, intensity ratio 0.2
15), 7.3 (s, intensity ratio 0.015)

[0065]
When this polymer was thermally analyzed, Tg was observed at two temperatures of -48.9°C and -41.9°C, and the melting point was 54.3°C. For comparison, a similar thermal analysis was performed on a high polymer of ε-caprolactone, and the Tg
The temperature was 12.1°C, and the melting point was 65.6°C. Thus, the presence of two Tg's suggests that the obtained polymer is a block copolymer consisting of two types of segments.

The obtained copolymer has 1 and 3 benzene rings.
, 5-position, it is judged to be a polysiloxane/porolactone copolymer star polymer containing a molecular structure in which three molecular chains as shown in formula (Va) extend from the 5-position.

[0067]

[Chemical formula 14]

Example 7 4,4-bis(hydroxymethyl) synthesized in Example 5
Similar experiments were conducted using butyl terminated polysiloxane star polymers. That is, 3.74 parts of the polymer was dissolved in 84.7 parts of toluene, and 1.6N of n
-1.25 parts of n-hexane solution containing butyllithium was added. 7.36 parts of ε-caprolactone was added to this solution, and the same procedure as in Example 6 was carried out to obtain a colorless and transparent solid.

The obtained copolymer has 1 and 3 benzene rings.
, judged to be a polysiloxane-polylactone copolymer star polymer containing a structure in which three molecular chains, each containing two polylactone chains, are branched at the bonding site and extend from the 5-position, as shown in formula (Vb). be done.

[0070]

[Chemical formula 15]

Claims (2)

[Claims] Claim 1: A polysiloxane block represented by the general formula [Chemical 1] (where x represents a number from 5 to 100; Me represents a methyl group), and a polysiloxane block represented by the general formula [Chemical 1] (wherein x represents a number from 5 to 100; Me represents a methyl group), and a polysiloxane block represented by the formula [Chemical 2] at the tip of the siloxane chain. or [Chemical Formula 4] (wherein, a represents a number from 3 to 5; the silicon atom is bonded to the siloxane chain) through a bonding portion of the formula [Chemical Formula 4] (wherein, E is 1. A polysiloxane/polylactone block copolymer comprising a polylactone segment represented by a terminal group; b represents a number from 3 to 5; and y represents a number from 1 to 200. Claim 2: Ring-opening polymerization of hexamethylcyclotrisiloxane using 1,3,5-benzentris(lithium dimethylsilanolate) as an initiator; The polysiloxane polyester according to claim 1, characterized in that it comprises a step of forming a bond represented by the formula (wherein a is as described above); and a step of anionic ring-opening polymerization of a lactone. A method for producing a lactone block copolymer.