JPH10195315A - Hydrophilic soft polymer composition and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a hydrophilic soft polymer compsn. which is excellent in mechanical strengths in spite of its being supersoft and excellent also in hydrophilicity and water absorption properties by homogeneously dispersing a supersoft polymer material in an org. polymer material. SOLUTION: This compsn. is produced by thermally melt mixing 100 pts. thermoplastic styrenic elastomer having an average mol.wt. of 150,000 or higher with 500-4,000 pts. mineral oil softener, 200-1,000 pts. cross-linked water-absorbing polymer, and 1-600 pts. hydrophilic polymer or oligomer as the surfactant at a specified temp. for a specified time. The production process comprises the step of predrying the elastomer and the water-absorbing polymer, the step of adding specified amts. of the softener and the hydrophilic polymer or oligomer in a temp.-controllable mixer, and the step of thermally melt mixing under stirring in an inert gas atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible polymer composition, and more particularly to a water-stopping agent having high water absorption, a soil water retention material, a cold insulation material, and the like.
The present invention relates to a soft polymer composition that can be used for various seals and packing materials, a dressing material for protecting a wound, a building material for preventing dew condensation, and the like.

[0002]

2. Description of the Related Art Conventionally, in the field of high molecular organic materials, there has been a demand for improvements in various functions and performances with the expansion of uses as materials, and among them, a soft elastomer having hydrophilicity has been desired. . As one of the measures to respond to such a demand, a large amount of a softening agent or a plasticizer is blended into a generally used high-molecular organic material,
Means for producing low hardness elastomers are commonly used.

[0003]

However, in the conventional rubber refining process, there is a problem that it is difficult to compound a large amount of a softener or a plasticizer with a polymer material. The reason is that if a Banbury mixer or a roll is used when kneading the above-mentioned polymer material and a softener or a plasticizer, slip between the mixer and the roll is likely to occur as the mixing ratio of the softener or the plasticizer increases. In other words, there are problems that effective kneading cannot be performed or that the kneading of the rubber material after kneading becomes difficult.

[0004] Further, by blending a large amount of a softening agent or a plasticizer into a high molecular weight organic material, the mechanical strength as a material,
For example, it is impossible to obtain a soft polymer material that can withstand practical use due to a decrease in tensile strength or elongation rate, which is a bottleneck in a substantial reduction in hardness in the rubber industry.

[0005] Further, an elastomer having a water absorbing function can be obtained by adding a water absorbing polymer to a high molecular weight organic material. However, in the case of this elastomer, neither the water absorbing function nor the mechanical strength can be satisfied. In fact, no effective soft polymer material has been obtained for use as a water stopping agent or soil water retention material.

Accordingly, the present invention solves the above-mentioned problems of the conventional high-molecular organic material, and uniformly disperses the ultra-soft polymer material in the high-molecular organic material, thereby obtaining an ultra-soft polymer material. Nevertheless, an object of the present invention is to obtain a hydrophilic soft polymer composition having excellent mechanical strength and excellent hydrophilicity, particularly excellent water absorption.

[0007]

According to the present invention, in order to achieve the above object, 100 parts of a styrene thermoplastic elastomer having an average molecular weight of 150,000 or more is added to a mineral oil softener 500 parts.
To 4000 parts, 200 to 1000 parts of a cross-linked type water-absorbing polymer, and 1 to 600 parts of a hydrophilic polymer or a hydrophilic oligomer as a surfactant, and heat-treated under predetermined temperature and time conditions. A hydrophilic soft polymer composition obtained by dissolving and mixing according to the following method, and as a method for producing the same, a styrene-based thermoplastic elastomer and a water-absorbing polymer are preliminarily dried to remove moisture, and then mixed in a temperature-controllable mixer. Provided is a method of adding a predetermined amount of an oil-based softener and a predetermined amount of a hydrophilic polymer or a hydrophilic oligomer, performing heat treatment under a predetermined temperature and time condition while stirring in an inert gas atmosphere, and performing dissolution mixing.

As mineral oil-based softeners, paraffin-based process oils, naphthene-based process oils, aromatic process oils, polymerized high-boiling strong aromatic oils, paraffin, liquid paraffin, white oil, petrolactam, petroleum sulfone Acid salt, Gilsonite, petroleum asphalt, mineral rubber, petroleum resin, coal tar, chroman indene resin is used,
As the crosslinked type water-absorbing polymer, a carboxylate polymer or a sulfonate polymer is used. Further, as a hydrophilic polymer or hydrophilic oligomer, cationic surfactants, anionic surfactants, nonionic surfactants, polyols or higher alcohols, glycerin, bisphenol A ethylene oxide adduct,
A water-soluble polymer such as bisphenol A adduct of propylene oxide and polyethylene oxide is used.

According to such a hydrophilic soft polymer composition,
By employing a styrene-based thermoplastic elastomer having an average molecular weight of 150,000 or more, a suitable amount of a mineral oil-based softener and a cross-linked type water-absorbing polymer and a hydrophilic polymer or a hydrophilic oligomer are blended and uniformly dispersed in this elastomer, The obtained composition has excellent mechanical strength despite its tensile strength and elongation rate being both large and ultra-soft, yet has high water absorption and surface contact angle, and has good affinity with water. A polymer composition is obtained.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Various examples of the hydrophilic soft polymer composition according to the present invention will be described below. In this embodiment,
100 parts of a styrene-based thermoplastic elastomer having an average molecular weight of 150,000 or more and 500 parts to 4000 parts of a mineral oil-based softener,
The basic composition is a hydrophilic soft polymer composition comprising 200 to 1000 parts of a crosslinked type water-absorbing polymer and 1 to 600 parts of a hydrophilic polymer or a hydrophilic oligomer as a surfactant.

If the ratio of the softener or plasticizer is less than 500 parts, there is a problem that the elastomer does not have fluidity and cannot be molded at a low pressure. On the other hand, if the ratio of the softener or the plasticizer is more than 4000 parts, the obtained elastomer becomes almost liquid, and the intended polymer composition cannot be obtained.

When the amount of the crosslinked type water-absorbing polymer is less than 200 parts, the water-absorbing effect is hardly obtained. When the amount of the water-absorbing polymer is more than 1000 parts, the fluidity of the elastomer is lowered and the moldability at low pressure is deteriorated.

When the amount of the hydrophilic polymer or hydrophilic oligomer is 1 part or less, the effect as a surfactant is not obtained. When the amount is more than 600 parts, problems such as contamination may be caused.

Examples of the mineral oil-based softener include paraffinic process oil, naphthenic process oil, aromatic process oil, polymerized high-boiling strong aromatic oil, paraffin, liquid paraffin, white oil, petrolactam, petroleum oil Sulfonate, Gilsonite, petroleum asphalt, mineral rubber, petroleum resin, coal tar,
Chromane-indene resin and the like.

Further, as a crosslinked type water-absorbing polymer,
Examples thereof include a carboxylate polymer represented by a polyacrylate and a sulfonate polymer represented by a polysulfonate.

Examples of the hydrophilic polymer or hydrophilic oligomer include a cationic surfactant represented by a quaternary ammonium salt, an anionic surfactant represented by a sulfonate, an adduct of phenol with polyethylene oxide, Non-ionic surfactants represented by polyethylene oxide adducts, polyethylene glycol esters, polypropylene glycol adducts of ethylene oxide to alcohols, polyols such as polyethylene glycol and polytetramethylene glycol,
Alternatively, higher alcohols, glycerin, addition of ethylene oxide to bisphenol A, adducts of propylene oxide to bisphenol A, and water-soluble polymers such as polyethylene oxide are also used.

In addition to the above, dioctyl phthalate (DO)
Plasticizers of phthalic acid derivatives such as P), maleic acid derivatives, trimellitic acid derivatives, glycol derivatives, itraphthalic acid derivatives, azelaic acid derivatives, itaconic acid derivatives, fatty acid derivatives, paraffin derivatives, adipic acid derivatives, sebacic acid derivatives, Plasticizers such as fumaric acid derivatives, citric acid derivatives, oleic acid derivatives, stearic acid derivatives, glycerin derivatives, sulfonic acid derivatives, epoxy derivatives, phosphoric acid derivatives, and monoester plasticizers may be added.

The method for producing the hydrophilic soft polymer composition of this embodiment will be described below. That is, after preliminarily drying 100 parts of a styrene-based thermoplastic elastomer having an average molecular weight of 150,000 or more and 200 parts to 1000 parts of a crosslinked type water-absorbing polymer to remove water contained therein, 500 parts to 4000 parts of a mineral oil-based softener. Part and hydrophilic polymer or hydrophilic oligomer 1
Parts to 600 parts are dissolved and mixed by heating at about 150 ° C. to 200 ° C. in an inert gas atmosphere while stirring using a mixer or a separable flask capable of controlling the temperature, and the hydrophilic soft polymer composition Generate The stirring time and the stirring speed may be determined according to the dispersion of the composition.

More specifically, in this embodiment, an ACM mixer (manufactured by Aikosha Seisakusho Co., Ltd.) is employed as a stirrer at a temperature of 200 ° C. in a nitrogen gas atmosphere and a stirring time of 4 hours.
The mixture was treated at a stirring speed of 217 rpm for 0 minutes to obtain a desired hydrophilic soft polymer composition.

According to Table 1, a predetermined mineral oil-based softener and a crosslinked type water-absorbing polymer were blended with three kinds of styrene thermoplastic elastomers and three kinds of hydrophilic polymers or hydrophilic oligomers having different blending ratios. For each of the samples of Examples 1 to 5 and Comparative Examples 1 to 4 obtained by heating and dissolving and mixing based on the production conditions described above,
Tensile strength (kg / cm ² ), 500% modulus (kg / cm ² ), elongation (%), surface contact angle, water absorption (%, normal temperature 22 hours) and water absorption (%, 55 ° C. 22 hours) The result of the measurement is shown.

[0021]

[Table 1]

In Table 1, A is a styrene-based thermoplastic elastomer, B is a mineral oil-based softening agent, C is a cross-linked type water-absorbing polymer, D is a hydrophilic polymer or a hydrophilic oligomer. The Septon 40
55 (Kuraray Co., Ltd.) has an average molecular weight of about 200,000, Septon 4077 (Kuraray Co., Ltd.) has an average molecular weight of about 250,000, and Clayton G1650 (manufactured by Shell Petrochemical Co., Ltd.) used as a comparative example has the same molecular weight. 100,000.

IP Solvent 2835 for Mineral Oil Softener B
(Made by Idemitsu Petrochemical Co., Ltd.) is paraffin. In addition, Sunfresh ST500D is used as the crosslinked type water-absorbing polymer C.
(Manufactured by Sanyo Chemical Co., Ltd.), and as a hydrophilic polymer or hydrophilic oligomer D, New Ball 50HB55 (manufactured by Sanyo Chemical Co., Ltd.), cation SF75PA (manufactured by Sanyo Chemical Co., Ltd.),
Alcox (manufactured by Meisei Chemical Co., Ltd.) was used.

The tensile strength (kg / cm ² ), the 500% modulus (kg / cm ² ), and the elongation (%) in the measurement items were measured according to JIS K6301 test method. The surface contact angle is a characteristic item for checking the affinity with water, and the surface contact angle was determined based on a droplet method. Water absorption rate is JIS K6
258.

The operation of the droplet method will be briefly described with reference to the drawings. As shown in FIG. 1, the amount of liquid is adjusted by turning a micrometer of a droplet adjuster while looking at an optical microscope.
A droplet 2 having a diameter of 2 mm or less is formed at the tip of the. Next, the sample is placed on the sample stage 3, the sample stage 3 is gradually raised, and the surface of the sample 4 is brought into contact with the droplet as shown in FIG. 2, and the sample stage 3 is lowered to the original position. Then, as shown in FIG. 3, the droplet 2 separates from the tip of the needle 1 onto the sample 4.

Next, by turning the rotating ring of the optical microscope,
The 45 ° lines 5, 6 of the book and the curved surface of the droplet 2 are symmetrically contacted. Then, as shown in FIG. 4, the height h of the apex of the droplet and the length r of the radius of the bottom surface of the droplet are measured from the sample 4, and the surface contact angle θ is determined as θ = 2θ ₁ = 2 tan ⁻¹ (h / R).

According to Table 1, as in Comparative Examples 1, 2, and 4, Kraton G1650 (manufactured by Shell Petrochemical Co., Ltd.) having a mean molecular weight of about 100,000 as a styrene-based thermoplastic elastomer.
In the case where is used, regardless of other mixtures, the properties are poor in both the strength and the fluidity, and cannot be put to practical use. In Comparative Example 3, Septon 4055 (manufactured by Kuraray Co., Ltd.) was used as the styrene-based thermoplastic elastomer. However, since the content of the mineral oil-based softener B was 400 parts, there was almost no fluidity and the properties were poor. ing.

On the other hand, in Examples 1 to 5, each of the obtained compositions has a large tensile strength of 2 (kg / cm ² ) or more, an elongation of 1500% or more, and a water absorption rate of A sample is immersed in water and has a high water absorption rate of 100% or more at room temperature for 22 hours (excluding Example 4) or 1000% or more at 55 ° C. for 22 hours, and has a surface contact angle of 90%. ° C. or less, a composition having good affinity for water was obtained.

[0029]

As described above in detail, according to the hydrophilic soft polymer composition and the method for producing the same according to the present invention, a mineral oil softener is added to a styrene thermoplastic elastomer having an average molecular weight of 150,000 or more. A suitable amount of a water-absorbing polymer and a hydrophilic polymer or a hydrophilic oligomer are blended and uniformly dispersed to form a super-soft, yet excellent mechanical strength, a large water absorption and a large surface contact angle, and an affinity for water , A soft polymer composition having a good value can be obtained. Therefore, in the rubber refining process, a large amount of a softening agent or a plasticizer is blended into a polymer material and kneading is prevented, which prevents slippage between a mixer and a roll, which enables effective kneading and a rubber material after kneading. It will be easier for you to do so.

In particular, by optimally determining the mixing ratio of the above components with respect to the high molecular weight organic material, the mechanical strength such as tensile strength and elongation required of the material is high, and a water-stopping agent having high water absorption or soil water retention is required. It can be used as a material, various seals and packing materials, a dressing material for wound protection, a building material for dew condensation prevention, and the like, to provide a soft polymer material that can withstand practical use.

[Brief description of the drawings]

FIG. 1 is an enlarged view of a main part of a first stage for measuring a surface contact angle of a sample obtained in this embodiment.

FIG. 2 is an enlarged view of a main part of a second stage for measuring a surface contact angle according to FIG. 1;

FIG. 3 is an enlarged view of a main part of a third stage for measuring a surface contact angle.

FIG. 4 is an enlarged view of a main part in a final stage of measuring a surface contact angle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Needle 2 ... Droplet 3 ... Sample table 4 ... Sample 5, 6 ... 45 degree line

Claims (5)

[Claims] 1. A mineral oil-based softening agent is added to 100 parts of a styrene-based thermoplastic elastomer having an average molecular weight of 150,000 or more.
To 4000 parts, 200 to 1000 parts of a cross-linked type water-absorbing polymer, and 1 to 600 parts of a hydrophilic polymer or a hydrophilic oligomer as a surfactant, and heat-treated under predetermined temperature and time conditions. And a hydrophilic soft polymer composition obtained by dissolving and mixing. 2. Mineral oil-based softeners include paraffinic process oils, naphthenic process oils, aromatic process oils, polymerized high-boiling strong aromatic oils, paraffin, liquid paraffin, white oil, petrolactam, Petroleum sulfonate, Gilsonite, petroleum asphalt, mineral rubber, petroleum resin, coal tar,
The hydrophilic soft polymer composition according to claim 1, wherein one of the chroman indene resins is used. 3. The hydrophilic soft polymer composition according to claim 1, wherein a carboxylate polymer or a sulfonate polymer is used as the crosslinked type water-absorbing polymer. 4. As a hydrophilic polymer or a hydrophilic oligomer, a cationic surfactant, an anionic surfactant, a nonionic surfactant, a polyol or a higher alcohol, glycerin, an adduct of ethylene oxide with bisphenol A, 4. The hydrophilic soft polymer composition according to claim 1, wherein a water-soluble polymer such as an adduct of propylene oxide and polyethylene oxide is used for bisphenol A. 5. After pre-drying a styrene-based thermoplastic elastomer and a water-absorbing polymer to remove water, a predetermined amount of a mineral oil-based softening agent and a hydrophilic polymer or a hydrophilic oligomer are mixed in a temperature-controllable mixer. In addition, a method for producing a hydrophilic soft polymer composition, wherein a heat treatment is carried out under a predetermined temperature and time condition while stirring in an inert gas atmosphere to dissolve and mix.