JPS5938983B2 - Hydrophilic resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resin composition, and more specifically, a hydrophilic resin composition that absorbs water or swells by absorbing water, but is insoluble in water, and is a synthetic resin. Improving the water absorption of synthetic fibers, various water-stopping agents, waterproof paints, preventing condensation on films, improving the appropriate temperature properties of synthetic leather, various water-retaining agents, paper diapers,
The purpose of the present invention is to provide a novel hydrophilic resin composition that has a wide range of uses such as sanitary products, water-containing cold pillows, water-containing ice packs, and water-containing poultices.

In the past, various hydrophilic resins have been developed as materials for the above applications, but these conventional hydrophilic resins either have low absorption or swelling properties in water, or if these properties are improved, they become less soluble in water. It has the disadvantage that it has a great tendency to leak into water and cannot maintain its shape, and on the other hand, increasing its shape retention reduces water absorption and water swellability, and makes molding very difficult. have.

As a result of intensive research to solve the drawbacks of conventional hydrophilic resins, the present inventor found that it has extremely high hydrophilicity, absorbs a large amount of water and swells, and does not dissolve or leach in water. When a hydrophilic resin that can maintain its shape is developed and blended into a medium such as a natural or synthetic resin, this blend can be easily molded into the desired shape, and this blend can be easily molded into a medium such as a natural or synthetic resin. The present invention was completed based on the finding that strong water absorption and water swelling properties are still maintained even in the blended state of . That is, the present invention consists of a hydrophilic resin and a medium, and the hydrophilic resin has an average molecular weight of about 1,000.
0 or more hydrophobic constraint segments (hereinafter referred to as hard segments).

) about 5 to 90% by weight and about 95 to 10% by weight of a segment containing an ethylenically unsaturated group having an average molecular weight of about 1,000 or more (hereinafter referred to as an unsaturated segment), and at least one segment in the molecule. α, β-
A resin obtained by graft polymerizing an ethylenically unsaturated carboxylic acid or a derivative thereof and hydrolyzing it to a carboxylic acid when the derivative is used, and the medium is a natural or synthetic resin or a liquid medium containing these resins. This is a hydrophilic resin composition characterized by the following. To explain the present invention in detail, the first feature of the present invention is that a specific hydrophilic resin is used as the hydrophilic resin in the composition of the present invention.

This hydrophilic resin has the above-mentioned basic structure, and is a raw material polymer mainly composed of Protscopolymer, which has at least one bond type (hard segment * unsaturated segment valve hard segment) in the molecule. It is obtained by modifying and making it hydrophilic by a specific method. In the above, the hard segment is a polymer portion that tends to form a crystalline phase or a highly aggregated phase,
Examples include polystyrene, poly-alpha-methylstyrene, polyethylene, polypropylene, polyester containing aromatic rings, polyamide, and polyurethane. Therefore, polystyrene type and poly-α-methylstyrene type are preferred. Such hard segments have an average molecular weight of about 1,000 or more, preferably about 3,000.
It is preferred that the above amount is present in the raw material polymer in an amount of about 5 to 95% by weight, preferably about 10 to 80% by weight. If the lower limit of this range is exceeded, the resulting hydrophilic resin will have good water absorption and water swelling properties, but will have increased solubility in water.
Its shape retention and physical strength in water are reduced, making it similar to conventional hydrophilic resins. On the other hand, if the upper limit of the above range is exceeded, the resulting hydrophilic injection resin will have insufficient water absorption and water swelling properties. Note that the water absorption, water swelling flexibility, shape retention, physical strength, etc. described above do not only change depending on the amount of hard segments present, but also vary depending on the type and amount of hydrophilic groups in the hydrophilic resin in the present invention. It also changes depending on.

Such hard segments have a strong tendency to form a crystalline phase or a highly aggregated phase in the hydrophilic resin used in the present invention at temperatures below the softening point, and when a hydrophilic segment having a hydrophilic group absorbs water, , or act as a constraining phase that limits its tendency to dissolve in water. The unsaturated segment is a polymer containing an α,β-ethylenically unsaturated group in its structure and having an average molecular weight of about 1,000 or more, preferably about 3,000 or more, such as polybutadiene, polychloro Typical examples include Brene, polyisoprene, and unsaturated polyester.

This unsaturated segment is about 95-5,
Preferably it is present in an amount of about 90-20% by weight. Outside this range, results tend to be the opposite of those in hard segments. The above-mentioned hard segment and the above-mentioned unsaturated segment are bonded in the form of (hard segment * unsaturated segment * hard segment) in the raw material polymer, so-called telekeel type, multi-type, linear type, or radial type. The hard segment is sandwiched between at least two points of the unsaturated segment, and therefore, when this unsaturated segment is later made into a hydrophilic injection,
This hydrophilic part absorbs water and swells, but because the hydrophobic bonding phase is bonded to both ends, it does not dissolve or elute in water, and has sufficient shape retention and physical strength even in water. It has.

Therefore, if the above bonding type exists, there is no problem even if the single type (hard segment*unsaturated segment) is mixed. The above raw material polymer is hydrophilicized by graft polymerization of α,β-ethylenically unsaturated carboxylic acid or its derivatives onto the unsaturated double bonds of the raw material polymer, and when a derivative is used, additional carboxylic acid is added. This is done by hydrolyzing.

The above α,β-ethylenically unsaturated carboxylic acid or its derivative includes (meth)acrylic acid (this term includes both acrylic acid and methacrylic acid).

(same below), alkyl esters of (meth)atalylic acid such as methyl, ethyl, propyl, butyl, octyl, lauryl, stearyl, glycidyl, etc., (meth)acrylamide, (meth)acrylonitrile, itaconic acid derivatives, maleic anhydride derivatives, etc. There is. Any of these monomers can be used alone or as a mixture. The kraft polymerization method can be carried out according to conventionally known radical polymerization methods.

For example, using a raw material polymer, a monomer, a polymerization initiator, and necessary auxiliary materials, at a temperature of about 30 to 100°C, about 0.
Graft polymerization is carried out by bulk polymerization, suspension polymerization, solution polymerization, etc. for 5 to 2,500 hours, preferably about 1 to 20 hours, and if necessary, the grafted portion is made hydrophilic to obtain the hydrophilic property of the present invention. can get.

As the polymerization initiator used in the above-mentioned graft polymerization, any conventionally known polymerization initiators such as organic peroxides, inorganic peroxides, and azo compounds can be used, but peroxide-based ones are particularly preferred.

The grafting rate varies depending on the type of raw material polymer and monomer used, but is usually about 2.5 parts by weight or more, preferably about 5 to 500 parts by weight, per 100 weight parts of the raw material polymer. By changing this grafting ratio, the water absorption and water swelling degree of the resulting hydrophilic resin can be changed from several times to several tens of times. The hydrophilic resin obtained as described above exhibits various unique properties when compared with hydrophilic resins obtained from ordinary polymers or copolymers.

Conventional hydrophilic resins do not have both high water absorption (or water swellability) and high shape retention (or physical strength) in water. In contrast, the hydrophilic resin of the present invention does not bleed out into the water even when it absorbs water and swells up to 70 to 80 times in water, does not lose its shape, and has excellent physical strength. That's what I'm doing. Such a unique effect is derived from the backbone structure of the hydrophilic resin in the present invention.

In other words, even if the hydrophilic segment absorbs a large amount of water and swells several tens of times, the hydrophilic segment breaks apart and elutes because both ends of this segment are restrained by the crystalline phase of the hydrophobic hard segment. There is no such thing. The hydrophilic resin of the present invention, which has the above-mentioned unique properties towards water, can be molded alone if the introduced hydrophilic part is nonionic or ionic, but the proportion thereof is small. Although it is possible, if the hydrophilic part is ionic and its proportion is high (preferable case in the present invention), it will be difficult to mold the resin alone, and it will be difficult to mold it using not only water but also various organic media. It also becomes an insoluble note.

The second feature of the present invention is that the hydrophilic resin as described above is dispersed and mixed in various media, preferably at a concentration of about 5 to 95% by weight, and can be subjected to any desired molding process. 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 maintain its hydrophilic properties. It is a surprising finding that the inherent performance of the resin is demonstrated. The medium used in the present invention is a natural or synthetic resin or a liquid medium containing them, and these medium resins may be monomers, oligomers, or mixtures thereof that can form polymers or polymers. good. These media include:
For example, thermoplastic resins include polyester, polyamide,
Condensation polymers such as polycarbonate: Polyadducts such as polyurethane: ethylene, propylene, butene, vinyl acetate, styrene, vinyl halides, vinylidene halides, acrylonitrile, acrylic acid. , acrylic ester,
Homopolymers, mixed polymers, block polymers, or graft polymers of methacrylic acid, methacrylic acid esters, butadiene, chloroprehenoprene, and other addition-polymerizable monomers, natural rubber, butadiene rubber, styrene-butadiene rubber, butadiene-acrylonitrile rubber, Rubbers such as chloroprene rubber, isoprene rubber, butyl rubber, polysulfide rubber, silicone rubber, fluorocarbon rubber, urethane rubber, ethylene propylene rubber, chlorosulfonated polyethylene rubber, acrylic rubber: semi-synthetic resins such as acetyl cellulose, regenerated cellulose, There are other resins known as binders for Tanidane paints and printing inks.

Such natural or synthetic resins may be liquid or solid at room temperature, or may be dissolved or dispersed in an organic solvent. Although the hydrophilic resin used in the present invention is hydrophilic, it is insoluble in water and also in organic solvents.
Since it is sparingly soluble, it is preferable to use it in powder form when mixing it into the above-mentioned mouth-to-mouth medium, and the methods for mixing include conventionally known means of incorporating pigments and fillers into various base materials. It can be used as is.

For example, when mixing solids, any means such as a roll mill, Banbury mixer, kneader, extruder, spinning machine, etc. can be used depending on the purpose. In addition, even when mixed in a liquid medium, the methods used in conventional paint and printing ink technologies can be used as is. Further, when blending the above-mentioned two, the hydrophilic resin to be used may have a free ionic group or a salt form, which is determined depending on the purpose of use. 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, various organic solvents, plasticizers, various pigments, various fillers, ultraviolet absorbers, stabilizers, blowing agents, various inorganic salts,
Various alkaline agents, various acidic agents, etc. are used together in required amounts.
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, granules, various molded products, fibers, etc. Furthermore, it may be in the form of a so-called masterbatch or a final product. Such solid products include highly moisture-absorbing fibers, synthetic leather base materials, water-stopping materials for joints in various buildings and underground structures, and water-retaining and high-humidity control agents.
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 paint 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. As a result, the formed paint expands further, completely preventing further water intrusion. 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 quality of the pouring of these various articles can be improved. 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. As exemplified above, the resin composition of the present invention has many uses, each of which exhibits excellent effects.

Next, the present invention will be specifically explained with reference to Examples. In addition,
The words in the middle of the sentence or % are based on weight. Example 1
(Polystyrene * polybutadiene square polystyrene) (40% polystyrene) 5 parts of SBS telelock type block copolymer, 1 part of cyclohexane
0.00 parts of benzoyl peroxide, 0.05 parts of benzoyl peroxide, and 5 parts of methyl methacrylate were mixed and graft polymerized at 50°C for 20 hours to obtain a grafted block copolymer with a grafting rate of 80%.

This copolymer 1 was hydrolyzed according to a conventional method to obtain a sodium salt of the polymer 1, which was then washed, desalted, dried, and crushed to obtain a finely powdered resin. 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 out the excess water, and collected the water-swollen gel-like material. 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 (polystyrene content: 4091), 20 parts of naphthenic process oil
1 part and 30 parts of neoprene rubber in a heating roll.
Cross-wire dispersion was carried out at 20°C to 160°C. Next, this was molded into a string shape 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.

This material is hard enough to be manipulated with the fingertips, and its shape changes significantly by approximately doubling in length in 20 to 30 minutes, and it also shrinks in concentrated saline solution. It is useful for use in toys and toys.

Example 3 Using 100 parts of a block copolymer latex (concentration 30%) mainly composed of SBS telelock type (polystyrene-polybutadiene valve polystyrene) (30% by weight of polystyrene), 25 parts of acrylonitrile and 0.2 parts of ammonium persulfate. A graft copolymer with a graft ratio of 30% was obtained according to a conventional method.

This graft copolymer was hydrolyzed according to a conventional method to obtain a sodium salt of the graft polymer. The degree of water swelling of this hydrophilic resin was approximately 40 times. Glass beads were added to 16 parts of the hydrophilic resin powder obtained above, 20 parts of a 20% toluene solution of chloroprene rubber, and 64 parts of toluene and dispersed in a paint conditioner to prepare a fine dispersion of a hydrophilic resin. .

50 parts of the above hydrophilic resin fine dispersion and 70 parts of a 20% toluene solution of chloroprene rubber were uniformly mixed to obtain a solid composition.

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

After air drying, it was pre-dried at 60°C and then dried at 80°C for 3 hours. When this treated fabric was exposed to water, the coating material expanded and the fabric's weave closed. Furthermore, when this water-absorbed cloth was dried, its breathability was restored to a considerable extent. Similarly, flannelette, twill fabric, nylon pile fabric,
Urethane bulletproof cloth, nylon knit cloth, etc. coated, impregnated, or treated in sheet form are useful as water leakage prevention materials such as packing materials for joints that come into contact with water or sealing materials for seams such as jet fabrics. Ta.

Example 4 Methyl methacrylate was grafted onto a telechelic copolymer mainly composed of (poly-α-methylstyrene → 1,000-polyisoprene → 1,000-poly-α-methylstyrene) (30% poly-α-methylstyrene). The sodium salt of the graft block copolymer obtained by polymerization (grafting ratio 20%) and subsequent hydrolysis had a water swelling degree of about 5 times, and was useful as a resin for preventing condensation. .

Claims (1)

[Scope of Claims] 1. Consisting of a hydrophilic resin and a medium, the hydrophilic resin comprises a hydrophobic constraint segment (with an average molecular weight of about 1,000 or more)
Hereinafter referred to as hard segment. ) about 5 to 90% by weight and about 95 to 10% by weight of a segment containing an ethylenically unsaturated group having an average molecular weight of about 1,000 or more (hereinafter referred to as an unsaturated segment), and at least one segment in the molecule. α, β-
The resin is obtained by graft polymerizing an ethylenically unsaturated carboxylic acid or a derivative thereof, and if a derivative is used, hydrolyzing it to a carboxylic acid, and the medium is a natural or synthetic resin or a liquid medium containing these resins. A hydrophilic resin composition characterized by the following.