JPS5941459B2 - Water-soluble polymer composition - Google Patents

Description

[Detailed description of the invention] The present invention relates to novel water-soluble polymer compositions.

Among water-soluble polymer substances, polyvinyl alcohol is a well-balanced substance that exhibits excellent physical properties in many aspects such as adhesive strength, film strength, protective colloidal properties, and stability.
It is prized as a general-purpose water-soluble polymer. However, on the other hand, when trying to obtain a water-soluble polymer composition that exhibits even better performance by using it in combination with other types of water-soluble polymer substances, when these compositions are dissolved in water,
There are drawbacks such as separation into two layers, non-uniformity of the formed film, and failure to exhibit as good physical properties as expected, making it impossible to obtain the desired combined effect. In general, from thermodynamic considerations, it is known that the compatibility of solutions of two types of polymers dissolved in a common solvent comes down to the problem of free energy of interaction, and there is a special mutual interaction between molecules. It is generally accepted that if there is no effect, there is a lack of compatibility.

The case of aqueous solutions of polyvinyl alcohol and other types of polymers is no exception, and methyl cellulose other than polymers having many carboxyl groups that have an affinity for the hydroxyl groups of polyvinyl alcohol, such as polyacrylic acid, carboxymethyl cellulose, or sodium alginate, Hydroxyethyl cellulose, hydroxypropyl cellulose, polyethyl oxide, polyacrylamide, vinyl acetate-maleic acid copolymer, starch, gelatin, casein, etc. are not compatible with polyvinyl alcohol. and,
Since such studies and predictions from a thermodynamic standpoint are possible to some extent, attempts to improve this compatibility have been considered hopeless and have rarely been attempted, and there have been no successful cases. It doesn't exist at all. The present invention provides a novel water-soluble polymer composition that provides an aqueous mixture solution with good compatibility, and is composed of phosphorylated polyvinyl alcohol and a water-soluble protein.

In order to improve the compatibility between polyvinyl alcohol and other water-soluble polymers, ionic functional groups are introduced into polyvinyl alcohol, and -OH groups, which are hydrophilic groups in water-soluble polymers,
It is possible to strengthen the interaction with -NH2 groups, -COO- groups, etc., but in this case, common sense estimates that it is necessary to introduce several tens of mole % of ionic functional groups.

On the other hand, there are various difficulties in introducing such a large amount of functional groups. For example, when a phosphoric acid group is selected as the ionic functional group, when trying to increase the degree of phosphorylation to 10 mol% or more,
It is necessary to react with polyvinyl alcohol and more than the same amount of urea or phosphoric acid, and the product is difficult to purify as it contains a large amount of unreacted substances and by-products, and it also increases the degree of phosphorylation. Under such reaction conditions, the crosslinking reaction of polyvinyl alcohol with phosphoric acid occurs, and the water solubility of the product is likely to be lost, making it extremely difficult to control the reaction appropriately.
For this reason, it was considered hopeless to improve the compatibility of polyvinyl alcohol with other water-soluble polymers by such a method. However, contrary to common sense, the present inventors have discovered that by introducing at most about 1 mol% of phosphoric acid groups into polyvinyl alcohol, the compatibility with water-soluble proteins can be increased to a practically sufficient level. We have now completed the present invention.

The composition of the present invention maintains a stable and uniform state for a long period of time when made into an aqueous solution, so it can be widely used in applications that take advantage of the characteristics of both components. It offers many advantages, including good target surroundings.

The phosphorylated polyvinyl alcohol used in the present invention is
Usually, it can be suitably produced by subjecting polyvinyl alcohol and phosphoric acid to a heating reaction in the presence of urea, but it is not limited thereto.

The degree of phosphorylation is 0.5 mole? ~10 moles? is appropriate. In addition, polyvinyl alcohol having an acetyl group, a urethane group, etc. in the same molecule in addition to a phosphoric acid group may be used, and depending on the use, polyvinyl alcohol having these functional groups may be preferable. There are no restrictions on the degree of polymerization. On the other hand, as water-soluble proteins, gelatin, casein, albumin, or variations thereof, which are soluble in a water-based solvent such as water or an alkaline aqueous solution, can be used, and gelatin is particularly preferred.

The mixing ratio of phosphorylated polyvinyl alcohol and water-soluble protein is arbitrary, but in order to exhibit the characteristics of both, one component should weigh between 5 and 95% of the total polymer. Preferably, the content is in the range of 10 to 90% by weight.

Various additives may be added to the composition of the present invention depending on the intended use.

The composition of the present invention includes adhesives, protective colloids, paint additives,
It can be used as a paper processing agent, fiber processing agent, thickener, etc.

Next, examples of the present invention and comparative examples will be given.

Example 1 Phosphated fully saponified polyvinyl alcohol with a degree of polymerization of 1720 and containing 2.1 mol% of phosphoric acid groups (abbreviated as P-1), or commercially available polyvinyl alcohol (degree of polymerization of 1720, completely saponified product, abbreviated as P-) ) and gelatin in various proportions shown in Table 1, in each case 10% by weight. When dissolved in water at a concentration of , the conditions at that time were observed, and the results were as shown in Table 1.

Example 2 In Example 1, when an aqueous solution containing gelatin and P-1 at a mixing ratio of 4:6 (weight ratio) was used for bonding paper, both initial tack and water resistance were excellent. , 10 weight of P-1 alone? When an aqueous solution was used, the initial tack was poor, and when a 10% by weight aqueous solution of gelatin alone was used, the water resistance was poor.

Example 3 P-1 or P- used in Example 1 and casein were
The mixtures in the various ratios shown in the table were dissolved in water at a concentration of 5% by weight in each case, and the conditions at that time were observed, and the results were as shown in Table 2.

Application example Polymerization degree 1510, phosphoric acid group 1.5 mole? , acetyl group 1
1.7 mol%, 3.4 mol of urethane group? A black ink containing 3% by weight of an equal weight mixture of phosphorylated polyvinyl alcohol (P-) containing gelatin and gelatin was prepared.

This product was extremely stable and had good gloss.
Polymerization degree 1510 and acetyl group 12.2 mole instead? When the same amount of commercially available polyvinyl alcohol was used, the black ink became non-uniform after 10 days and could no longer be used.

Claims (1)

[Claims] 1. A water-soluble polymer composition consisting of phosphorylated polyvinyl alcohol and water-soluble protein.