JPS62172027A - Method for imparting water resistance to acetoacetic ester group-containing water-soluble high polymer - Google Patents

Abstract

PURPOSE:To improve water resistance of acetoacetic ester group-containing water-soluble high polymer compound, by irradiating the compound with ultraviolet rays. CONSTITUTION:A diketene is added to a water-soluble high polymer compound (e.g., PVA resin, etc.,) or the compound is subjected to ester exchange so the compound usually contains 0.2-20mol% acetoacetic ester group. Then, the water content of the acetoacetic ester group-containing water-soluble high polymer compound is adjusted to preferably >=30wt%, a film, sheet, film of coating, molded article, etc., are produced and, for example, a film with 100mu is irradiated with ultraviolet rays at a light volume of 30X10<3>-300X10<3>muW/cm2 per second for about 0.5-10sec. An aqueous solution, etc., of the resin before molding may be irradiated with ultraviolet rays.

Description

[Detailed Description of the Invention] [Industrial Application Field 1] The present invention is directed to the ability to make water-soluble polymers containing acetoacetate-resistant ester groups, particularly polyvinylalfur-based + and l fats containing acetoacetate groups, water-resistant. )ノ:Regarding.

[Prior art] Polyvinyl alcohol (fat) is used for applications such as adhesives, paints, and films, taking advantage of its water solubility, adhesiveness, and peeling properties; however, it has the disadvantage of poor water resistance. There is.

However, polyvinyl alcohol (one method to make moon oil water-resistant is to introduce acetoacetate groups into polyvinyl alcohol, add metal salts, formaldehyde, urea or melamine tumethylol, and aldehyde groups at both ends of the molecule). A method of making water resistant by adding a crosslinking agent such as polyvinyl alcohol having
Methods of irradiating electron beams or radiation such as β-rays, γ-rays, and X-rays have been proposed.

[Problems to be Solved by the Invention] However, when metal salts are used, there is a risk that the coloring will be noticeable during heating and drying, and depending on the type of metal, toxicity may be a problem. The use of polyvinyl alcohol + 1 fat, which has aldehyde groups at both ends of the molecule, is not desirable from an environmental and hygienic point of view as removal of residual formalin is a national problem. Heat treatment or drying must be carried out under strong conditions such as heat treatment at 100°C for 1 to 16 hours, and such post-treatment is disadvantageous in terms of process, and in applications such as adhesives and paints, high temperatures are In some cases, heat treatment or drying is not possible. Furthermore, when such a water resistant agent is added to an aqueous polyvinyl alcohol resin solution, there is a risk that the solution will thicken or gel, and great care must be taken in adjusting the pot life.

In this respect, water resistance methods using electron beams or radiation can be said to be advantageous as there is almost no concern about coloring or gelation, but depending on such irradiation methods, the water resistance of polyvinyl alcohol resins containing acetoacetate groups may not always be sufficiently improved. The problem remains that it cannot be done.

In today's era of technological innovation, polyvinyl alcohol, which has been widely used due to its inherently water-soluble property, requires a fairly high degree of water resistance in its final use. Given the current situation in which polyvinyl alcohol is required to have both of the above, the search for a method for making it even more water resistant than before is an essential technical challenge for the development of uses for polyvinyl alcohol.

[Means for Solving the Problems] However, as a result of extensive research, the present inventors have developed a water-soluble polymer containing 7-cetoacetic ester groups, particularly a water content of 20% by weight.
The present inventors have discovered that when the above acetoacetate group-containing water-soluble polymer is irradiated with ultraviolet rays, water resistance is significantly improved, and the present invention has been completed.

The water-soluble polymers mentioned above in the present invention include starch, oxidized starch, starch derivatives such as dialdehyde starch,
Methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose,
Examples include cellulose derivatives such as hydroxybutyl methyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, 7-methyl hydroxybrobyl cellulose, and aminoethyl hydroxypropyl cellulose, but the most important are polyvinyl alcohol resins containing acetoacetate groups. It is.

The polyvinyl alcohol resin containing an acetoacetate group in the present invention is obtained by adding diketene to polyvinyl alcohol Q (fat) or transesterifying acetoacetate. Examples include partially or completely saponified polyvinyl esters such as polyvinyl acetate, as well as monomers that are mainly vinyl acetate and can be copolymerized with it, such as unsaturated carboxylic acids or their parts or complete esters, salts, anhydrides, and 7-amides.・Acetalization, urethanization, and ether of polyvinyl alcohol and polyvinyl alcohol, which are saponified copolymers with nitrile, unsaturated sulfonic acid or its salt, α-olefin having 2 to 30 carbon atoms, vinyl ether, etc. "Post-modified" polyvinyl alcohols that have been modified, grafted, phosphoric acid esterified, etc. may also be used.

The content of 77-toacetate groups in the above i-sealing resin is 1.
1, (') Although it is possible to maintain water solubility at 5 mol% or more, it is usually 0.1 to 40 mol%.
, especially in the range of <0.2 to 20 mol%. If the content of acetoacetate groups is extremely low, the purpose of water resistance cannot be achieved. Furthermore, even if a larger amount of 7cetoacetate groups is introduced than necessary, the effect of imparting water resistance will not be further improved, and the water solubility will often be lost. Also, the preferred polyvinyl alcohol resin (?
, degree is 60-99.9 mol%, degree of polymerization is 200-3.0
It is 00.

(When irradiating fat with ultraviolet rays, the moisture content should be reduced to 2.
It is necessary to adjust the content to 0% by weight or more (20 parts or more of water per 100 parts by weight of resin, the same applies hereinafter) or more, preferably 30% by weight or more. If the water content is less than 20% by weight, a sufficient improvement in water resistance cannot necessarily be expected. The water content can be adjusted by any method, such as spraying water onto powder, granules, pellets, etc. of polyvinyl alcohol resin containing 7 cetoacetate groups, or spraying water on polyvinyl alcohol a tl Ill containing 7 cetoacetate groups. film from aqueous solution,
A sheet, a coating film, a molded product, or the like may be produced and dried appropriately to a predetermined moisture content. Alternatively, the aqueous solution may be directly irradiated with ultraviolet rays.

The aqueous solution may contain fillers, colorants, surfactants, fibers, foaming agents, antifoaming agents, crosslinking agents, waterproofing agents, photocuring accelerators, water-soluble substances (sealants, water Dispersible resins, rice and wheat property improvers, etc. may be added.

As described above, the acetoacetate group-containing polyvinyl alcohol resin that has been adjusted to have a predetermined water content is irradiated with ultraviolet rays. Any light source may be used, and examples include a low-pressure mercury lamp, a high-pressure mercury lamp, a high-pressure mercury lamp, a carbon arc lamp, and a Kusemen lamp. The wavelength of the light i source is usually 10 (
It takes about 1 to 50 (',) r++n. For example, for a 100μ film, the irradiation amount is 1)
30 x 10 ~ 300 x 10] μW/clll
A suitable amount of light is between 0.5 and 1 C1. If the irradiation is too small, a water-resistant effect that can withstand boiling water cannot be expected. On the other hand, if the irradiation is too high, the effect will increase accordingly. Otherwise, it becomes uneconomical and impractical.

In the ultraviolet treatment described in L, heat treatment, water resistance treatment, etc. may be used in combination, if necessary.

The waterproofing method of the present invention can be applied to various uses of polyvinyl alcohol resins containing acetoacetate groups. Its uses are listed below.

(1) Molded product-related fibers, films, sheets, vibrators, tubes, bottles,
A molded object such as a container is manufactured and then irradiated with ultraviolet light.

(2) Adhesives Preferably, adhesives that include a base material that can transmit ultraviolet rays as part of the bonding target, pressure-sensitive adhesives, re-ta agents, non-woven fabric paint goo, fibrous paint goo, true melt adhesives, pressure-sensitive adhesives After adhering to the agent, it is irradiated with ultraviolet light.

(3) Coating agent Clear coating agent for paper, pigment coating agent for paper, sizing agent for paper, pine goo for thermal recording paper, overcoating agent for thermal recording paper, sizing agent for textile products, fiber processing agent, leather finishing agent , paints, antifogging agents, metal corrosion inhibitors, antistatic agents, etc.: Irradiate with ultraviolet rays.

(4) Hydrophobic 1 (Blends for oils) UV irradiation is applied in applications such as antistatic agents for hydrophobic resins, hydrophilic external additives, composite fibers, additives for films and molded products, etc.

Ultraviolet rays can be irradiated as necessary for various uses such as emulsifiers, suspending agents, thickeners, flocculants, soil conditioners, hydrogels, photosensitizers, and electrosensitive agents.

[Function 1] As described above, the method of the present invention is particularly useful as a method for making molded products, coating materials, etc. waterproof.

1 Example] Next, the method of the present invention will be explained in more detail by giving an example. "F%" is by weight unless otherwise specified.

Example 1 Polymerization degree], +81) 0, 10% of acetoacetate-esterified polyvinyl alcohol with a degree of acetoacetate esterification of 3 mol% obtained by reacting diketene with polyvinyl alcohol with a saponification degree of 98 mol% Pour the aqueous solution onto polyethylene terephthalate (polyethylene terephthalate) and dry until the moisture content reaches 100% to create a transparent film with a thickness of 1 (10 μm).

)Use a W high-pressure mercury lamp to irradiate ultraviolet rays from a height of l f, ', l cm for 2 hours. This film 2
0 cmX? Cut into (',) cm, temperature I O
When il''C was immersed in boiling water for 1 hour, the degree of water swelling and water output rate were measured.

1] The measured value was according to the following formula.

j4 (1 baffle is shown in the table.

G8 Examples 1-3 Electron for the same film as Example 1! <Reference example])
, was irradiated.

As Reference Example 2, the same method as Example 1 was carried out except that unmodified polyvinyl alcohol (degree of saponification 98 mol %, degree of polymerization 1, 80 i) was used.

Further, as Reference Example 3, the method of Example 1 was carried out except that the moisture content of the film was changed to 8%.

These results are also listed in the table.

Examples 2 to 5 Ultraviolet treatment was carried out under various conditions as shown in Table I-2. The results are shown in the table.

(hereinafter referred to as "margin") (hereinafter referred to as margin) [Effect of the invention 1 In the present invention, when a water-soluble polymer containing acetoacetate groups is irradiated with ultraviolet light under conditions where the water content is 20% by weight or more,
Remarkable water resistance that can withstand boiling water can be achieved.

Claims (1)

[Scope of Claims] 1. A method for making a water-soluble polymer containing acetoacetate groups water resistant, which comprises irradiating the water-soluble polymer containing acetoacetate groups with ultraviolet rays. 2. The method for making water resistant according to claim 1, characterized in that an acetoacetate group-containing water-soluble polymer having a water content of 20% by weight or more is used. 3. The water-resistant method according to claim 1, wherein the water-soluble polymer is a polyvinyl alcohol resin.