JP2803155B2 - Chloroprene block copolymer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a chloroprene block copolymer. More specifically, packing, adhesives, shoe soles,
The present invention relates to an ABA-type triblock copolymer having chloroprene in an intermediate block, which can be used for materials such as hoses, tubes, and automobile parts.

[Prior Art] There have been several reports on the production of copolymers of chloroprene and various monomers. For example, cationic graft copolymerization with isobutyl vinyl ether [Journal of Macromolecular Science (J. Macromo
l.Sci.,) A14, Issue 5, p. 729, 1980], Ion alternating copolymerization with acrylonitrile [Journal of Macromolecular Science (J. Macromol. Sci.,) A6
Volume 3, No. 439, 1972] and radical copolymerization with vinylpyridine [Chung-Kuo K'O Hsueh Yuan Ying Ha]
u Hsueh Yen Chiu So Chi K'an., Vol. 7, p. 26, 1963]
Etc. are known.

However, an ABA-type triblock copolymer having chloroprene as an intermediate phase is not known. ABA type block copolymer is styrene-butadiene-styrene (SBS)
As represented by the production of a block copolymer, it is generally produced by a living anionic polymerization method.
Therefore, ionic polymerization of chloroprene has been studied conventionally [for example, Vysokomol. Soyed., Vol. 6, No. 9, p. 1637, 1964.
Vysokomol.Soyed.3, 5, 798, 1961, Vyos
okomol. Soyed. 19, 12, 2793, 1977, etc.]. However, the interaction between the chlorine atom of the chloroprene monomer and the metal-based catalyst is very large, and the removal of the chlorine atom and the deactivation of the catalyst are likely to occur.

[Problems to be Solved by the Invention] The present invention has been made in view of the above, and provides an ABA-type triblock copolymer having chloroprene in an intermediate block.

[Means for Solving the Problems] That is, the present invention provides a chloroprene polymer block composed of a chloroprene monomer residue (M ₁ ) and a chloroprene polymer block represented by the following general formula (1): (In the formula, R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, an allyl group or an alkoxy group.) M ₂₎
Chloroprene block copolymer composed of a polymer block composed of at least one of acrylic acid, acrylic acid ester, methacrylic acid and methacrylic acid ester, which is represented by the following general formula (2): (Wherein, M ₁ represents a chloroprene monomer residue, M ₂ represents the above-mentioned acrylic acid, acrylate, methacrylic acid, and methacrylic acid ester monomer residue, and R ₃ and R _{4 each} have 1 carbon atom. Represents an alkyl group of _{4 to 4. Even if} R ₃ and R ₄ are the same,
It can be different. Here, n and m are both 20 to
This is a natural number of 5000. ).

The block copolymer of the present invention has the following general formula (3) (Wherein, R ₃ and R ₄ represent an alkyl group having 1 to ₄ carbon atoms).
R ₂ and R ₄ may be the same or different. ) And is synthesized using an initiator having a plurality of dithiocarbamate groups. A method for producing an ABA-type block copolymer using this initiator is known per se (for example, Jpn. Polymer, Vol. 40, p. 583, 1983).

The ABA type block copolymer of the present invention is synthesized by the following two-step reaction utilizing this reaction.

First, chloroprene is photopolymerized using a dithiocarbamate compound represented by the general formula (3), (Wherein, R ₃ and R ₄ are as described above; M ₁ represents a chloroprene monomer residue; n is a natural number of 20 to 5000). obtain.

Next, using this as an initiator, at least one of acrylic acid, acrylic acid ester, methacrylic acid, and methacrylic acid ester monomer represented by M ₂ in the general formula (2) is photopolymerized to obtain a desired ABA-type A block copolymer is obtained.

Examples of the methacrylate monomer used in the present invention include methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, and methacrylic acid.Examples of the acrylate monomer include methyl acrylate, Ethyl acrylate, n-butyl acrylate, isobutyl acrylate, hexyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, isononyl acrylate, decyl acrylate,
Stearyl acrylate, hydroxyethyl acrylate,
Examples thereof include 2-methoxyethyl acrylate, 2-ethoxyethyl acrylate, 2-butoxyethyl acrylate, and acrylic acid.

In any of the first-stage and second-stage photopolymerization reactions, the wavelength required for decomposition of the dithiocarbamate and generation of radicals,
For example, ultraviolet rays of 300 to 500 nm are used.

There is no problem if the first-stage and second-stage polymerization reactions are carried out in any state of lump, suspension, dispersion, slurry, and emulsion.

As a solvent used for the solution polymerization, an aromatic hydrocarbon solvent such as benzene, toluene, xylene, and ethylbenzene, and a solvent such as ethyl acetate which does not have characteristic absorption to ultraviolet rays of 300 to 500 nm and has a small chain transfer constant are preferable. The polymerization is carried out under deoxygenation or under an inert atmosphere such as nitrogen or argon. There is no problem if the polymerization temperature is in the range of -80 to 100C, but 0 to 50C is most preferable.

〔The invention's effect〕

According to the present invention, chemical resistance, weather resistance, acrylic acid ester excellent in dyeability, methacrylic acid ester, acrylic acid, and a methacrylic acid monomer residue as a terminal block,
An ABA type block copolymer having chloroprene rubber as an intermediate block having excellent chemical stability and oil resistance can be obtained.

EXAMPLES Hereinafter, the present invention will be described with reference to Examples, but the present invention is not limited thereto.

The analysis method and conditions used for identification and qualification of the copolymer of the present invention are described below.

(1) Infrared absorption spectrum (IR) Model JASCO IR-810 infrared spectrophotometer Measurement method Casting method on NaC1 base (2) Proton nuclear magnetic resonance spectrum (H-NMR) Model Varian EM360A NMR Spectrometer (3) Gel permeation chromatography (GPC) Model TOSOH HLC-802ACP-8III (Data processing unit) Packed column Styrene-divinylbenzene copolymer gel TSKgel G7000H6 / G6000H6 / G3000H8 system Measurement conditions Column temperature 38 ° C Flow rate 1.8ml / min Peak detection Differential Refractometer Eluent Tetrahydrofuran Example 1 Polymerization was carried out by the following procedure using a photochemical reactor (100 W mercury lamp UVL-100HA built-in) manufactured by Riko Kagaku Sangyo Co., Ltd. The monomers, the solvent and the initiator were used for polymerization after sufficiently drying and degassing by a conventional method.

After sufficiently replacing the reactor with nitrogen, the following structural formula 0.6 g of paraxylylenebis N, N diethyldithiocarbamate (hereinafter abbreviated as XDC) represented by
g and 56 g of a chloroprene monomer were charged and irradiated with ultraviolet light at 10 ° C. for about 20 hours with sufficient stirring under a nitrogen atmosphere.

After the completion of the polymerization, the reaction solution was purified by reprecipitation using a large amount of methanol, and dried under vacuum to obtain a chloroprene polymer in a yield of 74%. In addition, liquid chromatography confirmed that unreacted XDC was not contained in the produced polymer. Therefore, it is considered that XDC was all added to the chloroprene polymer.

When the molecular weight of the purified polymer was measured by gel permeation chromatography, the number average molecular weight (Mn) was 70,000 in terms of polystyrene, and the weight average molecular weight (Mw) was 192.
000.

Next, 6.75 g of the polymer and 100 g of benzene were charged into the reactor, and the polymer was completely dissolved. Subsequently, 16.20 g of methyl methacrylate was added and mixed well, followed by stirring.
Ultraviolet irradiation was performed at 30 ° C. for 20 hours to perform polymerization.

After the completion of the reaction, the content was poured into a large amount of methanol to precipitate, and 18.01 g of a polymer was obtained. All of the resulting polymers were soluble in acetone. Further, fractional precipitation was performed by adding methanol to an acetone solution of the produced polymer. When methanol was added in an amount 1.2 times the volume of acetone (volume ratio), precipitation of the polymer occurred, and the precipitate (a) and the dissolved substance (b) were separated. Yield 16.85g each
And 0.97 g.

The fractions (a) and (b) were subjected to IR and H-NMR measurements. As a result, as shown in FIGS. 1 and 2, the polymer (a) contained both chloroprene and methyl methacrylate. The molar ratio of the monomer residues was chloroprene / methyl methacrylate = 0.625. On the other hand, the polymer (b) was a homopolymer of methyl methacrylate.

 The molecular weight of the produced polymer was as follows: polymer (a) Mn = 197,000 Mw = 416000 polymer (b) Mn = 65,000 Mw = 110,000

From the fact that the initiator is bifunctional and the above results,
The polymer (a) is an ABA comprising a methyl methacrylate polymer block A and a chloroprene polymer block B.
It is concluded that this is a type block copolymer.

Example 2 A block copolymer was synthesized under the same conditions as in Example 1 except that methyl acrylate was used instead of 16.20 g of methyl methacrylate used in Example 1.
The resulting polymer was purified by fractional precipitation using an acetone / methanol mixed solvent, and dried under vacuum. As a result, 1.10 g of a methyl acrylate homopolymer and 19.10 g of a polymer having a molar ratio of constituent monomer residues of chloroprene / methyl acrylate = 0.526 were obtained. The molecular weight of the latter copolymer is
Mn = 200000 and Mw = 453000. From the fact that the initiator used was bifunctional and the molecular weight changed, it was concluded that this polymer was an ABA-type block copolymer consisting of a methyl acrylate polymer block A and a polychloroprene block B.

[Brief description of the drawings]

1 and 2 show a proton nuclear magnetic resonance spectrum and an infrared absorption spectrum of the polymer (a) obtained in Example 1 of the present invention, respectively.

Claims (1)

(57) [Claims] 1. A chloroprene polymer block comprising a chloroprene monomer residue (M ₁ ) and a compound represented by the following general formula (1): (Wherein, R ₁ represents a hydrogen atom or a methyl group, R ₂ represents a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, or an alkyl group having 1 to 18 carbon atoms substituted with an alkoxy group or a hydroxyl group. .) Is a polymer block composed of at least one of acrylic acid, acrylic acid ester, methacrylic acid and methacrylic acid ester comprising a monomer residue (M ₂ ) represented by the following general formula (2). Chloroprene block copolymer. (Wherein, M ₁ represents a chloroprene monomer residue, M ₂ represents at least one of the above-mentioned acrylic acid, acrylic ester, methacrylic acid and methacrylic ester monomer residues, and R ₃ and R ₄ represent Represents an alkyl group having 1 to 4 carbon atoms, R ₃ and R ₄
May be the same or different. here,
Both n and m are natural numbers from 20 to 5000. )