JP3285622B2 - Block copolymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polyvinyl alcohol component and the aqueous solution is made of a polymer component having a cloud point,
The present invention relates to a block copolymer having a small temperature dependency of the viscosity of an aqueous solution and a method for producing the same.

[0002]

2. Description of the Related Art As a method for synthesizing a block copolymer containing crystalline polyvinyl alcohol as a component, various monomers are radically polymerized using polyvinyl acetate having a thiol group at a terminal as a chain transfer agent. a method for synthesizing is known by saponification (JP 59 -
189,111 JP).

[0003] As the method of synthesizing a block copolymer consisting of polyalkenyl ether component a polyvinyl alcohol component and the aqueous solution having a cloud point, in recent years, so-called living polymerization method (JP 62 - 257910 discloses, Sho 62
- 257911, JP-A No. 1 - 108202 Patent Publication No.
Distribution, JP 1 - 108 203 JP) have been found, using this method, after the block copolymer of benzyl vinyl ether and other alkenyl ether, by debenzylation, polyvinyl alcohol component And a method for synthesizing a block copolymer comprising a polyalkenyl ether component and a polyalkenyl ether component. However, this method has a problem that it is difficult to synthesize in large quantities because hydrogen bromide gas or sodium radical in liquid ammonia is used for debenzylation. In addition, polyvinyl alcohol obtained by debenzylation of polybenzyl vinyl ether has an isotactic structure, and is therefore compared with conventional polyvinyl alcohol having an atactic structure obtained by saponifying polyvinyl acetate. Therefore, it is reported that they are inferior in crystallinity, heat resistance and water resistance (K.
Fujii, J. et al. Polym. Sci. , Part
D, 5,431 (1971)). That is, conventionally, the block copolymer containing a component polyvinyl alcohol component having the properties of a crystalline polymer has not been known.

[0004]

The main object of the present invention is to solve the above polyvinyl alcohol component and an aqueous solution free from the above problems comprises a polymer component having a cloud point, the temperature dependence of the viscosity of the aqueous solution is less block copolymer An object of the present invention is to provide a polymer and a method for producing the polymer.

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above problems, first, a polyvinyl alcohol component and a compound selected from the chemical formulas (I) and (II) are selected.
Wherein the aqueous solution is composed of a polymer component having a cloud point, and the two components are linked by a sulfide bond . Secondly, the block copolymer has a thiol group at the terminal, and has a chemical formula (I) And formula (II)
The method for producing a block copolymer as described above, comprising polymerizing a vinyl ester in the presence of a polymer having at least one structure represented by an aqueous solution having a cloud point , and then saponifying the resulting polymer. And completed the present invention.

[0006]

Embedded image (Wherein, ^{R 1} represents a hydrogen atom or a methyl group, ^{R 2}
Is a hydrogen atom or a monovalent organic group (preferably having 1 to
10 organic groups, more preferably an organic group having 1 to 5 carbon atoms)
Is shown. n shows the integer of 0-10. )

[0007]

Embedded image (In the formula, R ³ represents a hydrogen atom or a methyl group.)

The block copolymer of the present invention is a block copolymer in which a polyvinyl alcohol component and an aqueous solution are composed of a polymer component having a cloud point, and both components are connected by a sulfide bond. Polyvinyl alcohol (hereinafter, referred to as
The component (which may be abbreviated as PVA) is composed of a vinyl alcohol unit and a vinyl ester unit, and has a saponification degree of preferably 70 mol% or more, and
The above is more preferable, and 95 mol% or more is more preferable.
The stereoregularity of the PVA component in the present invention is not particularly limited, but an atactic structure or a syndiotactic structure close to the atactic structure is preferred, and an atactic structure is more preferred. If aqueous solution at the present invention is a polymer component having a cloud point state, and are not aqueous polymer solution has a cloud point in the temperature range of 0 to 100 ° C., the cloud point of the polymer solution among them is 20 to 95 ° C. Is preferable, and the case where the temperature is 30 to 95 ° C. is more preferable.
Even more preferably, the temperature is 30 to 80C. The cloud point of these polymer aqueous solutions was 5% when a 1% by weight aqueous solution of the polymer was placed in a UV cell equipped with a temperature controller, a thermocouple and a stirrer, and the temperature was raised or lowered at a rate of 1 ° C./min.
00nm light transmittance is 100% to 0% (or 0%
From 100% to 100%).

[0009] The polymer component aqueous solution having a cloud point in the present invention, prior Symbol of formula (I) and polyalkenyl ethers of formula (II) (The Society of Polymer Science Proceedings, Vol.40, No. 6, P. 1710) and poly-N-isopropylacrylamide (poly-N-isopropylmethacrylamide) (J. Phys. Chem., 9).
3,3311 (1989)) Ru Der.

The number average molecular weight of the polymer component having a cloud point in the aqueous solution in the present invention is not particularly limited.
500 to 1,000,000 is preferable, and 1000 to 100
000 is more preferred. The number average molecular weight of the polymer component in the aqueous solution having a cloud point in the present invention is measured by size exclusion chromatography, and can be determined in terms of standard polystyrene.

The block copolymer of the present invention is obtained by polymerizing vinyl esters in the presence of a polymer having a thiol group at a terminal and having an aqueous solution having a cloud point, and then saponifying the resulting polymer. Can be Polymer having a thiol group at a terminal serving as a chain transfer agent in the method for producing a block copolymer of the present invention and having an aqueous solution having a cloud point
And is to have a thiol group at the terminal, represented by the formula (I)
Have a thiol group polyalkenyl ethers and ends that
And poly N-isopropyl acrylamide (poly N-isopropyl methacrylamide) represented by the chemical formula (II )
It is. The alkenyl ether has the following chemical formula
Those having an oxyethylene chain in the side chain represented by (III) are preferred.

[0012]

Embedded image (Wherein, ^{R 4} represents a hydrogen atom or a methyl group, ^{R 5}
Represents a hydrogen atom or a monovalent organic group. n shows the integer of 0-10. )

R ⁵ in the formula (III) represents a monovalent organic group (preferably an organic group having 1 to 10 carbon atoms, more preferably an organic group having 1 to 5 carbon atoms).
Examples include an aryl group, an aralkyl group, an alkenyl group, an alkoxyalkyl group, and an aryloxyalkyl group. They may be substituted by hetero groups. The above alkenyl ether units may be used alone or in combination of two or more. Further, a block copolymer obtained by polymerizing one or two or more alkenyl ethers, adding another alkenyl ether, and further polymerizing the alkenyl ether may be used. Specifically as alkenyl ether, methyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, propoxyethyl vinyl ether, butoxyethyl vinyl ether, 2 - methoxyethoxy ethyl vinyl ether, 2 - ethoxy ethoxyethyl vinyl ether, 2 - methoxy - 2 - ethoxyethoxy ethyl vinyl ether, 2 - ethoxy - 2 - ethoxy ethoxyethyl vinyl ether, phenoxyethyl vinyl ether, methoxyethyl propenyl ether, ethoxyethyl propenyl ether, propoxyethyl propenyl ether, butoxyethyl propenyl ether, 2 - methoxyethoxy propenyl ether,
2 - ethoxyethoxy ethyl propenyl ether, 2 -
Methoxy - 2 - ethoxyethoxyethylpropenyl ether, 2 - ethoxy - 2 - ethoxyethoxyethylpropenyl ether, phenoxyethylpropenyl ether and the like can be mentioned.

[0014] Poriarukenirue over ether which at one end in the present invention having a thio Lumpur groups can be obtained by the following method. And Arukenirue chromatography ether having a thiocarbonyl ester bond in a side chain represented by the following formula (IV),
An addition compound with a proton-supplying compound represented by the following chemical formula (V) is polymerized as a polymerization initiation terminal.

[0015]

Embedded image (Wherein, ^{R 6} represents a hydrogen atom or a methyl group, ^{R 7}
Is an alkyl or aryl group such as a methyl, ethyl, propyl, butyl, phenyl group (preferably having 1 to 1 carbon atoms)
An alkyl group or an aryl group of 0, more preferably an alkyl group or an aryl group having 1 to 5 carbon atoms), and n represents an integer of 1 to 5. )

[0016]

Embedded image (In the formula, X represents an anionic group.)

Specific examples of the compound of the formula (V) include:
For example ants acid, acetic acid, propionic acid, butyric acid, pivalic acid,
Fluoroacetic acid, chloroacetic acid, bromoacetic acid, difluoroacetic acid, dichloroacetic acid, dibromoacetic acid, trifluoroacetic acid,
Trichloroacetic acid, tribromoacetic acid, hydrogen chloride, hydrogen bromide, hydrogen iodide, dialkyl phosphate, monoalkyl phosphate, methanesulfonic acid, trifluoromethanesulfonic acid, p-toluenesulfonic acid, phenol and the like. And trifluoroacetic acid are particularly preferred.

The alkenyl ether is polymerized by a living cation polymerization method known in the art (JP-A-60-228509).
JP, JP-A-61-103654, JP-Sho 62-
257910 JP, Lewis acid or protonic acid initiator usable in JP-A-1-108202及<br/> beauty Hei 1-108203 discloses), can be carried out using an additive and a solvent, the polymerization The temperature is preferably at most 60 ° C, particularly preferably at most + 40 ° C. When synthesizing a polyalkenyl ether having a thiol group at one end,
Usually, monohydric alcohols are used as polymerization terminators.
The content of the alkenyl ether unit is not particularly limited, but is preferably 50 mol% or more, more preferably 70 mol% or more, and still more preferably 90 mol% or more.

[0019] Poly N- isopropylacrylamide having a thiol group at one terminal in the present invention, similar to the preparation of polyvinyl alcohol polymer having a thiol group in a known end (JP 59-187003 JP) Can be synthesized by various methods.

The block copolymer of the present invention has a thiol group at a terminal and is selected from the chemical formulas (I) and (II).
An aqueous solution is obtained by polymerizing vinyl esters in the presence of a polymer having a cloud point and then saponifying the resulting polymer. Examples of the vinyl esters used in the present invention include vinyl acetate, vinyl benzoate, vinyl pivalate, and vinyl trifluoroacetate. As the polymerization method in the present invention, bulk polymerization, solution polymerization,
Conventionally known polymerization methods such as pearl polymerization and emulsion polymerization can be used. Having a thiol group at the terminal and having the chemical formula (I)
And at least one structure selected from the chemical formula (II)
The amount and the method of addition of the polymer having the cloud point represented by the aqueous solution to the polymerization system and the method of addition are not particularly limited, and are appropriately selected according to the physical properties of the target block copolymer. The polymerization in the present invention is carried out using a usual radical polymerization initiator. As the radical polymerization initiator, such as 2, 2 '- azobisisobutyronitrile (hereinafter, A
IBN), benzoyl peroxide, lauroyl peroxide, diisopropyl peroxycarbonate, potassium persulfate, and ammonium persulfate.

[0021] The number average molecular weight of the block copolymer in the present invention, the polyvinyl alcohol component re acetylation polymer, preferably 5,000 to 1,000,000. The molecular weight of the block copolymer of the present invention is measured by size exclusion chromatography, and is determined in terms of standard polystyrene. Also, the saponification degree of vinylalcohol Lumpur component, determined by quantitative acetates residues with ¹ H- NMR.

The block copolymer of the present invention has a wide range of properties by adjusting the composition and molecular weight of both components. Even at low temperatures, the aqueous solution viscosity is PV
P is lower than that of A, and the temperature dependence of viscosity is small.
Since it has properties different from VA, it is suitable for use as a processing agent for dispersants, resins, papers, fibers and the like.

[0023]

The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples.

Synthesis Example 1 A glass container equipped with a three-way stopcock was prepared, and after purging with nitrogen, nitriding was performed.
Pressurize in a raw gas atmosphere to remove the adsorbed water in the glass container
Was. 2 in the container−Methoxyethyl vinyl ether 200
ml, ethyl acetate 200 ml, and polymerization solvent toluene
Add 1540 ml and add 0.84 ml of trifluoroacetic acid
2−1.5 ml of vinyloxyethyl thioacetate
20 ml of the solution mixed in 25 ml of E
When the temperature reaches 0 ° CEt _1.5 AlCl
_1.5 (1.0M) in 40 ml of toluene
Started the match. After 4 hours, polymerize with 20 ml of methanol
Stopped. In this case, the polymerization rate is 100% (gas chromatography).
By size exclusion chromatography)ー
According to the standard standard measured in tetrahydrofuran at 55 ° C.
Number average molecular weight Mn = 22000 in terms of polystyrene.
Was. In addition, the terminal thiol groups of the polymer
Reaction with iodine and remove the remaining iodine with sodium thiosulfate.
The thiol group content at the end is determined by titration with
As a result, the introduction rate of the thiol group to one end of the polymer is
109%, quantitatively introducing thiol groups
I understood.

Example 1 240 g of vinyl acetate was dissolved in 60 g of methanol, the atmosphere was replaced with nitrogen, the temperature was raised to 60 ° C., and AIBN was used as an initiator.
After addition of methanol solution of 0.0434G, immediately poly 2 having a thiol group at one end obtained in Synthesis Example 1 - methoxyethyl vinyl ether (number average molecular weight M
n = 22000, Functionality f = 1.0
A methanol solution (119 g / l) of 9) was added to 1.7.
Polymerization was carried out by dropping at a rate of ml / 5 min. 1
After 10 minutes, the polymerization was stopped, and the polymer obtained by precipitating in hexane was dried under vacuum to obtain a polymer in a yield of 81 g. The resulting polymer was dissolved in methanol (concentration: 20%), and [NaOH] / [VAc] = 0.05
(Mole ratio), a methanol solution of NaOH was added, and the mixture was saponified at 40 ° C. to obtain a block copolymer (hereinafter sometimes abbreviated as B1).
The ¹ H -NMR block copolymer, a saponification degree of the PVA component was 99.9 mol%, vinylalcohol Lumpur units and 2 in the block copolymer - ratio of methoxyethyl vinyl ether units, 21/1 ( Molar ratio), 9.1 / 1
(Weight ratio). The copolymer obtained by re-acetylating the obtained block copolymer was subjected to size exclusion chromatography measured at 55 ° C. in tetrahydrofuran to obtain a number average molecular weight Mn = 11 in terms of standard polystyrene.
3000, weight average molecular weight Mw = 60000, Mw / M
n = 1.67.

Example 2 240 g of vinyl acetate was dissolved in 60 g of methanol, the atmosphere was replaced with nitrogen, the temperature was raised to 60 ° C., and AIBN was used as an initiator.
After addition of methanol solution of 0.0651G, poly 2 having a thiol group immediately one terminal - methoxyethyl vinyl ether (number average molecular weight Mn = 21000, functional Rithy f = 1.07) in methanol (1
(57 g / liter) was dropped at a rate of 3.5 ml / 5 minutes to carry out polymerization for 254 minutes, followed by saponification under the same conditions as in Example 1 to give a yield of 99 g and Mn = 600.
0, Mw = 114000, Mw / Mn = 1.89, degree of saponification 99.9%, vinylalcohol over the block copolymer <br/> Le units and 2 - the ratio of methoxyethyl vinyl ether unit of 5.5 / 1 (Molar ratio), 2.4 / 1 (weight ratio) of a polymer (hereinafter sometimes abbreviated as B2) was obtained.

Example 3 The temperature change of the viscosity of the aqueous solution (9 to 10% by weight) of the block copolymer obtained in Examples 1 and 2 was measured with an E-type viscometer. The result is shown in FIG. PVA homopolymer (for Kuraray, trade name: PVA-
EC, polymerization degree 1700, saponification degree 99.8% or more) and PVA homopolymer (manufactured by Kuraray, trade name: PVA-11)
7, the degree of polymerization is 1700, and the degree of saponification is 98.5 mol%).

Example 4 A film obtained by casting the aqueous solution of the block copolymer obtained in Examples 1 and 2 was subjected to a tensile test. Table 1 shows the results.

[0029]

[Table 1]

Table 1 clearly shows that the polymer obtained in Example 1 has the same elastic modulus and tensile strength as PVA homopolymer (PVA-EC).

[0031]

As is evident from the above examples, the block copolymer of the present invention is more effective than the PVA homopolymer.
Since the temperature dependence of the aqueous solution viscosity is low and has the same film strength as the PVA homopolymer, resin,
Since it is considered that it can be used as an ideal processing agent for paper, fiber and the like, it has extremely high industrial value. Further, according to the production method of the present invention, a block copolymer of a PVA component and a polymer component having an aqueous solution having a cloud point, which has been conventionally difficult to synthesize, can be synthesized by a relatively simple method.

[0032]

[Brief description of the drawings]

[1] PVA component and 2 - shows the temperature dependence of the viscosity of an aqueous solution of a block copolymer of methoxyethyl vinyl ether component.

[Explanation of symbols]

● PVA homopolymer (manufactured by Kuraray, trade name: PVA-
117, degree of polymerization 1700, degree of saponification 98.5 mol%, concentration 10 wt%), polymer obtained in Example 1 (B
1, concentration 10 wt%), polymer obtained in Example 2 (B2, concentration 10 wt%), PVA homopolymer (manufactured by Kuraray, trade name: PVA-EC, degree of polymerization 1700,
PVA homopolymer (manufactured by Kuraray, trade name: PVA-117, degree of polymerization 1700, degree of saponification 98.5 mol%, concentration 9 wt%)

Claims (2)

(57) [Claims] Claims: 1. A polyvinyl alcohol component and a compound
At least one selected from formula (I) and formula (II)
A block copolymer represented by a kind of structure, in which an aqueous solution comprises a polymer component having a cloud point, and both components are connected by a sulfide bond. Embedded image (Wherein, ^{R 1} represents a hydrogen atom or a methyl group, ^{R 2}
Is a hydrogen atom or a monovalent organic group (preferably having 1 to
10 organic groups, more preferably an organic group having 1 to 5 carbon atoms)
Is shown. n shows the integer of 0-10. ) (In the formula, R ³ represents a hydrogen atom or a methyl group.) 2. A compound having a thiol group at a terminal and having the formula (I)
And at least one structure selected from the chemical formula (II)
2. The process for producing a block copolymer according to claim 1, wherein the polymer produced is polymerized in the presence of a polymer having a cloud point in an aqueous solution , and the resulting polymer is saponified. Embedded image (Wherein, ^{R 1} represents a hydrogen atom or a methyl group, ^{R 2}
Is a hydrogen atom or a monovalent organic group (preferably having 1 to
10 organic groups, more preferably an organic group having 1 to 5 carbon atoms)
Is shown. n shows the integer of 0-10. ) (In the formula, R ³ represents a hydrogen atom or a methyl group.)