JPS5938988B2 - Hydrophilic resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resin composition, more specifically a resin composition that absorbs water but does not dissolve in water, and has a wide range of uses such as various water stop agents and water retention agents. The purpose of the present invention is to provide a novel hydrophilic resin composition.

Conventionally, it has been used for the purpose of imparting water absorbency to synthetic resins, synthetic fibers, synthetic leather, and artificial leather, and for applications such as paper diapers, sanitary products, water-containing ice packs, water-containing poultices, water-containing cold pillows, and soil water retention agents. Various hydrophilic polymers have been developed for this purpose. In the case of hydrophilic derivatives that are themselves part of the material for the intended use, increasing their water-absorbing capacity or water-swelling performance will increase their tendency to dissolve or leach into water. It may become sticky or sticky.
In addition, they have the disadvantage that they cannot retain their original shape, and that increasing their shape retention makes it extremely difficult to mold them, so their water absorption capacity or water swelling performance must be low. It was hot. Also, starch,
Natural polymers such as gelatin and casein, semi-synthetic polymers such as mettrium carboxymethyl cellulose and methyl cellulose, polyvinyl alcohol, sodium polyacrylate, polyacrylamide, polyhydroxyethyl methacrylate, polyethylene oxide, polyvinylpyrrolidone, etc. Synthetic polymers and partially crosslinked products of the various water-soluble polymers mentioned above are used.

Of these, all non-crosslinked products are basically completely water-soluble polymers, and even if a gel-like product is formed as a result of water absorption, it is dissolved in water at a relatively high concentration, so it has poor fluidity. If water is added, a portion of the gel may start to dissolve or the gel may break and flow out. In addition, the water-absorbed gel-like material is so-called pudding-like and has insufficient physical strength. As an improvement to the above, water-soluble polymers can be cross-linked by radiation irradiation or by post-treatment such as heating or addition of catalysts, cross-linking agents, etc., and the swelling state can be improved by restricting the dissolution of molecules through network bonds. Efforts have also been made to stop water absorption. However, in order to reduce uncrosslinked molecules, that is, molecules that may elute, and to improve physical properties, it is necessary to increase the crosslink density, but this naturally increases the degree of water swelling, that is, water absorption. This results in a significant decrease in performance. Therefore, in order to have sufficient water absorption capacity, it is inevitable that a considerable proportion of the components that are necessarily solubilized remain.

Furthermore, since the cross-linking is done in the form of points, the physical strength of the water-absorbed material is insufficient. As a result of intensive research to solve the drawbacks of conventional hydrophilic injection resins, the present inventor found that they have extremely high water absorption, absorb a large amount of water and swell, and do not dissolve or leach out in water. We have developed a hydrophilic resin that can maintain its shape, and when it is blended with a medium such as a natural or synthetic polymer, it can be easily molded into the desired shape, and even in such a blended state, it still has strong water absorption properties. The present invention was completed based on the finding that water retention and water swelling properties were maintained.

That is, the present invention is a block copolymer consisting of a hydrophilic resin and a medium, in which the hydrophilic resin has at least one bonding form (hard segment x hydrophilic segment ÷ {hard segment) in the molecule; A hydrophilic resin composition characterized in that the hydrophilic segment is a polymer chain consisting of α, β ethylenically unsaturated carboxylic acid units, and the medium is a natural or synthetic polymer or a hydrophobic liquid medium. be. To explain the present invention in detail, the hydrophilic resin used in the present invention and which mainly characterizes the present invention has a bonding form of at least one hydrophilic segment (hard segment) in its structure. It is a block copolymer with

The hard segment in the above basic structure is a nail coalescing part that tends to form a crystalline phase or a highly aggregated phase, and examples include polystyrene, poly-α-methylstyrene, polyethylene, polypropylene, polyacrylonitrile, and polyurethane bonds. These are polymer chains such as polyester, polyamide, and polyvinyl halide containing aromatic rings.

This hard segment has a strong tendency to form a crystalline phase or an aggregated phase in the hydrophilic resin used in the present invention at a temperature below the softening point, and when the hydrophilic segment having a hydrophilic group absorbs water, acts as a constraining phase that restricts the tendency to dissolve in The hydrophilic segment is an interlocking chain consisting of alpha, beta monoethylenically unsaturated carboxylic acid units.

Since the hydrophilic group is ionic, this hydrophilic segment strongly absorbs water, contains water, and has a strong tendency to dissolve in water. The binding action of the segments prevents them from dissolving, so they absorb water and swell significantly, but they do not dissolve in water or ooze out and become sticky, and retain their shape. Examples of α,β-ethylenically unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, etc., and a combined chain consisting of such units can be prepared by using the above-mentioned free acids. Alternatively, a free carboxylic acid may be generated by hydrolyzing a merging chain consisting of a derivative such as an ester, nitrile, or amide of a free carboxylic acid as described above.

Further, it is preferable that the carboxylic acid of these time-combined chains is in the form of an alkali metal salt or a water-soluble amine salt. The manufacturing method will be explained in more detail as follows. (1) Block conjugation by condensation reaction of a bundle having a condensation group at the end.

Bifunctional polymers that are hydrophilic or can be made hydrophilic include, for example, acrylic acid, methacrylic acid, and their lower alkyl esters, which BAMFORD et al.
SACTIONSOFTTHEFARADAYSOCIE
The initiator δ,δ″-azobis(δ-sia) proposed in TY Vol. 56, No. 6, pp. 932-942 (1960)
By carrying out a polymerization reaction using a compound such as n-pentanol under conditions where termination of recombination is likely to occur, an aggregate having a hydroxyl group at the end can be obtained.

In addition, other hydrophobic functional polymers such as styrene, acrylonitrile, etc. can be used as well as δ, δ'-azobis (δ-
(Sia)-n pentanol) etc. to have a monohydroxyl group at both ends, and JACKSON has disclosed in U.S. Patent No. 3689.
Chain transfer agent 2- used in No. 593 (1972)
By polymerizing using mercaptoethanol or the like, it is obtained as having a hydroxyl group or the like at one end.
It can also be obtained by anion singing, for example, SH
IMURA JOURNALOFPO-LYMERSC
IENCE PARTC. /46.23, pages 803-808 (1968), after anionic polymerization, it is possible to deactivate the polymer by treating it with ethylene oxide, for example, so that it has hydroxyl groups at both ends.

As described by SHIMURA in the above-mentioned paper, these hydrophilic and hydrophobic polymers can be combined with urethane by reacting them with various diisocyanates such as tetramethylene diisozyanate. In the case of a group that can be converted into a hydrophilic group such as methyl ester, ethyl ester, or propyl ester, it can be obtained by post-treatment such as hydrolysis or saponification reaction.

(2) Synthesis of a block using an anionic lipping polymer.

(a) Stepwise block conjugation with monofunctional initiators.

For example, JOURNAL OF POLY by GRAHAM et al.
MERSCIENCE Vol. 44, pages 414 and 416 (
``Styrene-methyl methacrylate-acrylonitrile block triple combination'' described in 1960)
It can be obtained by further hydrolyzing or saponifying methyl ester.

(b) Stepwise cut copolymerization using a difunctional initiator.

For example, the above JOURNALOFPOLY-MERS
Examples include "acrylonitrile-isopropyl acrylate-acrylonitrile block copolymer" described on pages 3-4 and 416 of CIENCE, and "block copolymer of acrylonitrile-methylmethacrylate-acrylonitrile" described on pages 414 and 416, and isopropyl It can be obtained by hydrolyzing or saponifying ester or methyl ester. (d Monofunctional initiation coupling method.

For example, JOURNAL OF POLY such as FREYSS
MERSCIENCEPARTBPOL7YMERLE
TTERS Vol. 2, pp. 217-222 (1964) describes styrene-methyl methacrylate A by anionic coupling.
B-type block copolymers have been described, but when this anionic block copolymer is terminated, it is treated with a coupling agent such as a dihalogeno compound to deactivate it, thereby bonding two molecules to form an ABA-type block copolymer. I can do it,
It can be obtained by hydrolyzing or saponifying methyl ester.

(d) Coupling method by introducing a condensable group at the end of the molecule.

Styrene-methyl methacrylate A mentioned in (c) above
Upon termination of the anionic polymerization of the B-type protuberance,
SHIMURA et al.
As described in ERSCIENCE PARTC No. 23, pp. 803-808 (1968), ABA can be obtained by deactivating it by treating it with ethylene oxide, introducing a hydroxyl group at the end of the bundle, and linking it with a diisocyanate.
It can be obtained by hydrolyzing or saponifying the methyl ester thereof.

As mentioned above, the hydrophilic resin used in the present invention is composed of a combination of a hydrophobic hard segment and a hydrophilic segment, and the average molecular weight of each of these segments is about 10.
00 or more, preferably about 3000 or more, and the composition ratio of both is hard segment: hydrophilic segment 5 to 95.
(Amount of free time)%: 95-5%.

The degree of hydrophilicity of the obtained hydrophilic resin can also be changed by changing this composition ratio. When the above-mentioned hydrophilic resin has a large number of ionic groups, it is difficult to mold or apply it alone, so the resin should be used by mixing it into another medium.

By using it in this way, its molding process and method of use become very easy. Even if it is mixed into other media, especially natural or synthetic resins, the hydrophilic resin used in the present invention has a strong affinity for water, so it can overcome the cohesive force of such media and retain its hydrophilic properties. It is a surprising finding that the water absorption and water retention abilities of resins are demonstrated. The medium used in the present invention is a natural or synthetic polymer or a hydrophobic liquid medium.

Preferred solid media such as natural polymers and synthetic polymers used are natural rubber, polyptadiene, polyisoprene, polyisoptylene, butadiene-styrene copolymer, putadiene-acrylonitrile copolymer,
These include polychloroprene, ethylene-propylene rubber, acrylic compound, ethylene monovinyl acetate compound, polyvinyl butyral resin, silicone rubber, urethane rubber, etc., and examples of compound compound include random compound, graft compound, and block compound. Various co-claw copolymers are used, and among them, telelock type, multi-type, and radial type block copolymers are preferred because of their excellent strength. In addition, the hydrophobic liquid medium may be blended alone with the hydrophilic resin, or may be added to the aforementioned solid medium to improve flexibility, processability, feel, etc., and may include plasticizers, process oil, Preferred are oils, liquid paraffin, petrolatum, etc., and liquid polymers such as polyisobutene.

The solid medium and liquid medium as described above are preferably used alone or in the form of being dissolved or dispersed in an organic solvent.

Although the hydrophilic resin used in the present invention is ionic, it is insoluble in water, and is often insoluble or sparingly soluble in organic solvents, and also has the property of not melting.

Therefore, the hydrophilic resin is preferably used in the form of a fine powder or as a dispersion in an organic solvent.

Therefore, the means for mixing this hydrophilic resin with the above-mentioned solid or liquid medium or their organic solvent solution or dispersion is a conventionally known dispersing machine or mixer, such as a roll mill, a Banbury machine, etc. Preferably, a mixer, a second mill, a dispersion mill, a ball mill, a sand mill, etc. are used. Although the essential requirements constituting the resin composition of the present invention are as described above, various other additives may be optionally added depending on the purpose of use.

For example, water, surfactants, fragrances, various dyes and pigments, various fillers, ultraviolet absorbers, stabilizers, foaming agents, various inorganic salts, various alkaline agents, various acidic agents, etc. are used in required amounts. In addition, when blending the above-mentioned two, the hydrophilic resin used may have a free ionic group or a salt type, which is determined depending on the purpose of use.

Io-7l group-free types can be neutralized in the middle or final step of producing a resin composition to form a salt, or they can be injected with an appropriate alkali depending on the type of ion. It is also possible to mix an acidifying agent or an acidifying agent so that it is neutralized when water is absorbed. The hydrophilic resin used in the present invention has excellent advantages due to its structure as detailed above.

The ionicity of the hydrophilic group is thought to be the main factor, and it is possible to obtain products that have a fast water absorption rate or water swelling rate, and also have a very high water absorption capacity or swelling degree. Moreover, due to the restraints in its structure, it will not substantially dissolve in the water or seep out into the water.

Furthermore, since the water-containing swollen material is fixed by the restraining phase, it has superior physical strength compared to the conventional method using box points.

The resin composition of the present invention can take various forms, and can be broadly classified into solid and liquid at room temperature.

If it is in solid form, it may be in the form of powder, pellets, various molded products, fibers, impregnated products, etc. Furthermore, it may be in the form of a so-called masterbatch or a final product. Such solid products include highly hygroscopic fibers, synthetic leather base materials, water-stopping materials for joints in various buildings and underground structures, and sanitary products such as paper diapers, sanitary products, water-containing ice packs, and water-containing cold pillows. ,
As a medical product, it can also be used as a soil water retention agent, a water retention agent for growing seedlings, a humidity control material, a sweat-absorbing and hygroscopic base material for shoes and their insoles, and agricultural, forestry, and fishery products such as cold storage materials for fish and fruits. used. On the other hand, in the case of pasty or liquid products, there are paints, coating materials, processing agents, printing inks, etc., and they are particularly useful as paints.

For example, if such a coating material is applied to the joints, cracks, or joints of various structures, it will not only fill the gaps, but also prevent water from entering the area after filling. Therefore, the formed paint expands further, and further water intrusion can be completely prevented.
In particular, since the composition of the present invention repeatedly expands reversibly with water, it is expected to have a long-term waterproof effect. Further, when the liquid composition of the present invention is used as an impregnating agent for various articles, the surrounding quality of these various articles can be modified. Furthermore, when applied to the surface of dew-condensing materials such as various plastic films, glass or metal plates, it exhibits an excellent dew-condensation prevention effect. Next, the present invention will be specifically explained with reference to Examples.

In addition, parts or % in the text represent the amount of nails. Example 1 Styrene was polymerized using δ,δ'-azobis (δ-cyano-n-pentanol) as a polymerization initiator, and the average molecular weight was about 6.
000 polystyrene glycol was obtained.

Separately, a 4:1 mixture of methyl methacrylate and ethyl methacrylate was added to δ, δ'-azobis (δ-cyano-n-
Pentanol) was used as a synthesis initiator to obtain a military polymer whose main component was polymethacrylate glycol having an average molecular weight of about 17,000. Twice the equivalent amount of toluylene diisocyanate is added to 74 parts of this nail combination mainly composed of polymethacrylate glycol and reacted at 40 to 50°C, and then the above polystyrene diol is added thereto to form dibutyltin dilaurate. Mainly has a telechelic type structure (polystyrene now {methyl methacrylate-ethyl methacrylate (4:1) co-claw coalescence polystyrene) (polystyrene content 26%) obtained by reacting at 80 to 90°C as a catalyst. The ester bonds of the protox copolymer are saponified to obtain a hydrophilic resin mainly composed of (polystyrene, sodium polymethacrylate, polystyrene), which is dried and pulverized, and then passed through a 150-mesh sieve. A fine powder was obtained by sieving. To examine the degree of water swelling of this material, we accurately weighed approximately 0.2 grams of the sample, immersed it in 100 milliliters of distilled water at room temperature for 24 hours, filtered off the excess water, and collected the water-swollen gel. When accurately weighed, the water swelling degree was approximately 50 times greater.

30 parts of the above hydrophilic resin powder, 20 parts of styrene-butadiene thermoplastic rubber (40% polystyrene content), 20 parts of naphthenic process oil, and 30 parts of neoprene rubber.
The mixture was cross-dispersed at 120°C to 160°C using a heating roller.

This was then molded into a string to obtain a string-like sealing material.
When this was applied to the segment joints used in the Shield-E method, it exhibited a complete water-stopping effect.

Example 2 The hydrophilic resin powder obtained according to the method described in Example 1 was cross-dispersed in advance with a naphthenic process oil at a ratio of 50:50.

Similarly, copper phthalocyanine blue pigment was cross-dispersed with naphthenic process oil in a ratio of 40:60. Then, cross-dispersion was carried out using the above-mentioned composition using a heated two-roll mill.

It is hard enough to be manipulated with your fingertips, and its shape changes significantly by approximately doubling in length in 20 to 30 minutes in hot water or cold water.It also shrinks in concentrated saline solution, making it suitable for teaching materials. ,
Used for toys, etc.

Example 3 A styrene-methacrylate block copolymer similar to that in Example 1 (polystyrene content 13%) was saponified to form a telechelic type block copolymer mainly composed of (polystyrene, polysodium methacrylate, and polystyrene). The powder was obtained, dried, crushed and sieved to obtain a fine powder.

Glass beads were added to 16 parts of the hydrophilic resin powder obtained above, 20 parts of a 200 t toluene solution of chloroprene rubber, and 64 parts of toluene and dispersed in a paint conditioner to prepare a fine dispersion of the hydrophilic resin. .

A liquid composition was obtained by uniformly mixing 50 parts of the above hydrophilic resin fine dispersion and 70 parts of a 20 (fl) toluene solution of chloroprene rubber.

Separately, a jetted cloth was prepared and thoroughly impregnated with the above liquid composition.

Claims (1)

[Claims] 1 A block copolymer consisting of a hydrophilic resin and a medium, where the hydrophilic resin has at least one (hard segment, hydrophilic segment, hard segment) bond type in the molecule, and the hydrophilic segments are α, β. - A hydrophilic resin composition characterized in that it is a polymer chain consisting of ethylenically unsaturated carboxylic acid units, and the medium is a natural or synthetic polymer or a hydrophobic liquid medium.