JPH0236607B2 - HENSEIHORIBINIRUARUKOORU - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a novel modified polyvinyl alcohol (hereinafter referred to as PVA) into which a reactive group has been introduced.
In addition to the uses of conventional PVA, this new modified PVA has cross-linking properties and reactivity, so it can be used for reactive polymers, polymer catalysts, gel chromatography, affinity chromatography, ion exchange chromatography, etc. In addition to applications such as carriers, wall materials for microcapsules, photosensitive resins, and imparting water resistance to paper, new applications are expected by utilizing the reactivity of epoxy groups to introduce various functional groups. [Prior Art] PVA has been used in a wide range of applications such as emulsifiers, adhesives, paper coating agents, fiber sizing pastes, films, and synthetic fibers. Regarding the reactivity of PVA in these applications, most of them utilize the reactivity of the hydroxyl group in PVA. esters, thioglycolic acid esters, etc.), reactions between hydroxyl groups and isocyanates (xylylene diisocyanate, tolylene diisocyanate, etc.), inorganic compounds (H ₃ BO ₃ , TiO (SO ₄ ), Cu salts, etc.), etc. is well known. However, in terms of reactivity, the hydroxyl group of PVA is still not used industrially effectively due to the excessive number of reaction conditions and the difficulty of controlling the reaction state, and the residual unreacted reagent and toxicity. There are few examples of this. Furthermore, the idea of introducing a reactive group into PVA as a crosslinkable group is described in JP-A-58-76403 as a saponified product of a copolymer of a monomer having an alkoxymethyl group and vinyl acetate. However, there are no reactive polyvinyl alcohols that have been put into practical use industrially. In addition, as a method for introducing epoxy groups into PVA chains by post-denaturation, W. Lautsch. Journal of
The etherification method using epichlorohydrin of Polymer Science 8 191 (1952) can be used. [Problems to be solved by the invention] As mentioned above, the hydroxyl group of PVA requires extreme reaction conditions in terms of reactivity, and it is difficult to control the reaction state. There was a problem with toxicity. PVA with epoxy groups introduced through post-modification is also possible as a reactive PVA, but it has problems with reactivity and cannot be carried out easily or efficiently, and unreacted epichlorohydrin tends to remain as a residual monomer. In particular, because of the structure of the epoxy group, it cannot be stably maintained and crosslinking tends to occur during the reaction. The present invention was developed in view of the above circumstances, and is the result of extensive research aimed at obtaining PVA having a reactive group. [Means for solving the problem] The present invention has a formula of 0.01 to 10 mol% Structural unit represented by (epoxy group-containing monomer unit) and formula of 70 to 99.99 mol%

Indicated by [formula] structural unit (vinyl alcohol unit) and the formula for 0 to 29 mol%

〔Example〕

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples. The aqueous solution viscosity in each example is 4 at 20°C.
% aqueous solution using a B-type viscometer. Unless otherwise specified below, "parts" refer to parts by weight.
Moreover, "%" means weight %, respectively. Example 1 2000 parts of vinyl acetate was placed in a 3-separable flask equipped with a stirrer, a thermometer, a reflux condenser, and a dropping funnel.
220 parts of methanol, 0.6 parts of 2,2-azobisisobutyronitrile, and 10 parts of allyl glycidyl ether were charged, and after deoxidizing by bubbling nitrogen gas,
Polymerization was started when the temperature of the solution in the system reached 60°C due to heating, and from that point on, 10 parts of allyl glycidyl ether was dropped into the system over 4.5 hours, and copolymerization was carried out at 60°C for 5 hours. The solid content concentration of the copolymer is
It was 50.2% by weight. After removing unreacted monomers by blowing methanol vapor into the polymerization reaction solution, the copolymer was heated to 25% at 30°C.
A methanol solution of was prepared. When 18 parts of a 2.2N methanol solution of sodium hydroxide was added to 2,740 parts of this methanol solution and mixed, the system became viscous and particles precipitated after 75 minutes. After washing with methanol, the mixture was air-dried to obtain a white copolymer. The aqueous solution viscosity of this copolymer was 35 cps. The composition ratio of the copolymer is 0.6 mol% of vinyl acetate units,
The vinyl alcohol units were 97.9 mol% and the epoxy group-containing monomer units were 1.5 mol%. In addition, the number average molecular weight of the copolymer measured by GPC method was 2.5×
It was 10 ⁴ . The content of the epoxy group-containing monomer unit was determined by an acid cleavage method. The properties of the obtained epoxy-modified PVA are shown in the table. Examples 2 to 8 Copolymerization, saponification, and post-treatment were conducted in the same manner as in Example 1, except that the types and amounts of substances shown in the table were used as epoxy group-containing monomers. The properties of the obtained modified PVA are shown in the table. Comparative Examples 1-2 Unmodified PVA shown in the table was used. The results are shown in the table.

【table】

〔Effect of the invention〕

The present invention is a modified PVA that has epoxy groups that are expected to have various reactivities, and the water resistance of PVA can be improved by utilizing the reactivity of the epoxy groups, or by introducing new functional groups. We can expect many new applications.

Claims (1)

[Claims] 1 0.01 to 10 mol% formula A number average molecular weight of 8000 to 220000, consisting of a structural unit represented by , 70 to 99.99 mol% of a structural unit represented by the formula [formula], and 0 to 29 mol% of a structural unit represented by the formula [formula] Some modified polyvinyl alcohol. However, in the above formula, R ₁ , R ₂ , R ₃ and R ₄ are hydrogen atoms or alkyl groups, R ₅ is an alkyl group, and n ₁ is 1
or 2, n ₂ represents 1, 2 or 3;