JP2021050258A - Aqueous polyurethane resin composition for thin film body, thin film body, and method for manufacturing thin film body - Google Patents

Abstract

To provide an aqueous polyurethane resin composition for a thin film body, a thin film body and a method for manufacturing a thin film body which have transparency of a thin film body and can suppress permanent set remaining after a tensile force is applied.SOLUTION: A polyurethane resin composition for a thin film body contains an anionic aqueous polyurethane resin and a carbodiimide crosslinking agent (X) represented by the following formula (1). In formula (1), R1 represents a residue excluding a functional group reactive with isocyanate from a hydrophilic compound having a functional group reactive with isocyanate, R2 represents a divalent residue excluding an isocyanate group from a diisocyanate compound, and R3 represents a divalent residue excluding a hydroxyl group from a glycol compound. X represents a group formed by reaction of the hydrophilic compound and the diisocyanate compound. n1 represents a number of 1-10, n2 represents a number of 1-10, and m represents a number of 1-5. The plurality of R1 and R2 may be the same or different.SELECTED DRAWING: None

Description

The present invention relates to an aqueous polyurethane resin composition for a thin film body used for a medical film or the like, a thin film body, and a method for producing the thin film body.

In general, medical films and medical covers are often used by covering the devices of endoscopic cameras and medical probes. Materials used include natural rubber, polyisoprene, polyvinyl chloride, silicone rubber and the like. In the production of these thin films, a method of dipping into a mold having a specific shape or a method of laminating preformed films to each other is adopted. However, when natural rubber or polyisoprene is used, there is a problem that the transparency is lowered. On the other hand, in the case of polyvinyl chloride and silicone rubber, there are problems due to the low strength of the thin film body compared to other materials, the poor moldability, the difficulty of thinning the film, and the large permanent deformation. ..

In order to improve these problems, Patent Document 1 discloses an aqueous polyurethane resin composition containing an anionic water-based polyurethane resin and a carbodiimide-based compound having a specific structure capable of reacting with an anionic group as essential components. ing.

However, the thin film formed using this composition has low transparency, and the permanent strain remaining after applying a tensile force still tends to increase.

For this reason, when mounting a thin film body molded using the material described in Patent Document 1 on an endoscope or the like, considerable care is required and it takes time to mount the thin film body, which may hinder smooth work. there were.

In addition, the attached thin film body is also a cause of impairing the sharpness of the image.

Similarly, when it is used for a condom, there are problems such as transparency and permanent distortion, and improvement has been desired.

Japanese Patent No. 4497755

The problem to be solved is that the transparency of the thin film body is low, and the permanent strain remaining after applying a tensile force tends to be large.

The present invention has been realized as follows in order to make the thin film body highly transparent and to suppress the permanent strain remaining after applying a tensile force.

An aqueous polyurethane resin composition for a thin film body containing an anionic water-based polyurethane resin and a carbodiimide cross-linking agent (X) represented by the following formula (1) was prepared.

(In the formula, R ¹ represents a residue obtained by removing a functional group capable of reacting with isocyanate from a hydrophilic compound having a functional group capable of reacting with isocyanate, and R ² represents a divalent residue obtained by removing an isocyanate group from a diisocyanate compound. It represents a group, R ³ represents a divalent residue obtained by removing a hydroxyl group from a glycol compound, X represents a group formed by the reaction of the hydrophilic compound with the diisocyanate compound, and n1 represents a number of 1 to 10. , N2 represents a number from 1 to 10, m represents a number from 1 to 5. The plurality of R ¹ and R ² may be the same or different, respectively.)

The thin film body was formed by using the aqueous polyurethane resin composition for the thin film body.

A mold was immersed in the aqueous polyurethane resin composition for a thin film body, dried, and then peeled off to produce a thin film body.

The aqueous polyurethane resin composition for a thin film body of the present invention can improve the transparency of a molded thin film body and suppress permanent strain.

The water-based polyurethane resin composition for a thin film body of the present invention contains an anionic water-based polyurethane resin and a carbodiimide cross-linking agent (X) represented by the following formula (1).

(In the formula, R ¹ represents a residue obtained by removing a functional group capable of reacting with isocyanate from a hydrophilic compound having a functional group capable of reacting with isocyanate, and R ² represents a divalent residue obtained by removing an isocyanate group from a diisocyanate compound. It represents a group, R ³ represents a divalent residue obtained by removing a hydroxyl group from a glycol compound, X represents a group formed by the reaction of the hydrophilic compound with the diisocyanate compound, and n1 represents a number of 1 to 10. , N2 represents a number from 1 to 10, m represents a number from 1 to 5. The plurality of R ¹ and R ² may be the same or different, respectively.)

[Anionic water-based polyurethane resin]
The anionic aqueous polyurethane resin used in the present invention is a component contained in the anionic aqueous polyurethane emulsion. In this anionic aqueous polyurethane emulsion, a nonionic surfactant or the like is added to an emulsion (component dispersion) containing urethane. The anionic aqueous polyurethane emulsion is a self-emulsifying anionic aqueous polyurethane emulsion having an average particle size of less than 0.1 μm.

As the aqueous urethane resin, for example, polyols, carboxyl group-containing polyols, and carboxyl group-containing urethane-based prepolymers obtained from polyisocyanate compounds are used as a neutralizing agent and a chain extender in the presence of an organic solvent or water. Examples thereof include a resin obtained by reacting and then removing the solvent under reduced pressure. The anionic aqueous polyurethane resin is specifically an organic polyisocyanate (A), a polyol (B), a polyol (C) having a carboxyl group or a sulfonic acid group in the molecule, and a trifunctional chain extender if necessary. Is reacted to form a prepolymer, which is further added to water containing a neutralizing agent and, if necessary, an emulsifier, dispersed in water, and chain-extended by a well-known method.

The compound that can react with the anionic group used in the present invention can be blended at any stage in which the aqueous polyurethane resin composition of the present invention is produced. For example, it may be blended at the stage of polyurethane prepolymer or blended with an anionic water-based polyurethane resin.

Examples of the organic polyisocyanate (A) used for producing the anionic aqueous polyurethane resin include aliphatic, alicyclic and aromatic polyisocyanates, and specific examples thereof include tetramethylene diisocyanate and hexamethylene. Diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate ester, 1,3-cycloheximethylene diisocyanate, 1,4-cyclohexylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 2,4'-dicyclohexylmethane diisocyanate , 2,2'-Dicyclohexylmethane diisocyanate, isophorone diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'- Diphenylmethane diisocyanate, polyphenylpolymethylene polyisocyanate, m-phenylenediocyanate, p-phenylenediocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, 3,3'-dimethoxy-4,4'-biphenylenedi isocyanate, 1,5-naphthalene Examples thereof include diisocyanate and 1,5-tetrahydronaphthalenedisocyanate.

Examples of the polyol compound (B) used in the anionic aqueous polyurethane resin include conventional polyester polyols, polyether polyols, polycarbonate polyols, polycaprolactone polyols, and the like, and these may be used alone or in combination of several types. In particular, when a polyether polyol is used as all or part of the high molecular weight polyol compound, an anionic aqueous polyurethane resin having excellent elongation properties can be obtained, which is preferable.

Examples of the polyester polyol include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, and 1,4-butylene. Glycol, neopentyl glycol, 1,6-hexanediol, hexamethylene glycol, 3-methylpentanediol, trimethylolethane, trimethylolpropane, hexanetriol, glycerin, pentaerythritol, sorbitol, hydrogenated bisphenol A, etc. or their activities A polyol consisting of a low molecular weight polyol having two or more hydrogens and an adduct of alkylene oxide, and succinic acid, glutaric acid, adipic acid, sebatic acid, dimer acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, tetrahydrophthalic acid. , Polybasic acids such as endomethylenetetrahydrophthalic acid and hexahydrophthalic acid, or polyester polyols which are condensates with carbonic acid.

Examples of the polyether polyol include water, the low molecular weight polyol, or a compound having two or more active hydrogens such as ammonia, methylamine, ethylamine, aniline, phenylenediamine, and isophoronediamine, and an alkylene oxide (ethylene) having 2 to 4 carbon atoms. Additives of (oxide, propylene oxide, butylene oxide) can be mentioned, and more specifically, polyether polyols such as polyethylene glycol, polypropylene glycol, polyethylene / polypropylene glycol, polytetramethylene ether glycol, and polyhexamethylene glycol can be mentioned.

Examples of the polyol (C) having a carboxyl group or a sulfonic acid group include 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolvaleric acid, and 1,4-butanediol-2. -Sulfonic acid and the like can be mentioned. The amount of the polyol (C) having a carboxyl group or a sulfonic acid group to be used depends on the type of the polyol and the polyisocyanate used, but is usually with respect to all the reaction components constituting the anionic aqueous polyurethane resin. 0.5 to 50% by mass, preferably 1 to 30% by mass is used. If the amount of the polyol (C) used is less than 0.5% by mass, the storage stability is poor, and if it is used in excess of 50% by mass, the characteristics may be adversely affected.

Examples of the neutralizing agent for neutralizing the prepolymer include organic amines such as ammonia, trimethylamine, triethylamine, tripropylamine, tributylamine, N-methyldiethanolamine and triethanolamine, sodium hydroxide, potassium hydroxide and ammonia. Inorganic bases are mentioned, and these are used in sufficient amounts to neutralize the carboxy or sulfonic acid groups.

Examples of the emulsifier include well-known general anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, polymer-based surfactants, and reactive interfaces used in water-dispersible polyurethane resins. Activators and the like can be used. Among these, anionic surfactants, nonionic surfactants or cationic surfactants are preferable because they have a low cost and good emulsification can be obtained.

Examples of the amphoteric or cationic surfactant include alkyl betaines such as dodecyl betaine, alkyl pyridinium salts such as lauryl pyridinium-hydrochloride, and alkyl ammonium salts such as oxyethyl-dodecyl-ammonium chloride. Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, alkyl allyl formaldehyde condensed polyoxyethylene ether, polyoxyethylene oxypropylene block polymer, and polyoxyethylene polyoxypropylene alkyl ether as ether types. Examples of the ether ester type include polyoxyethylene ether of glycerin ester, polyoxyethylene ether of sorbitan ester, and polyoxyethylene ether of sorbitol ester, and examples of esters include polyethylene glycol fatty acid ester, glycerin ester, and polyglycerin ester. , Solbitan ester, propylene glycol ester, sucrose ester, and examples of the nitrogen-containing type include fatty acid alkanolamide, polyoxyethylene fatty acid amide, and polyoxyethylene alkylamine.

The polyoxyethylene alkyl ether is produced by adding 1 to 200 mol of ethylene oxide to a linear or branched primary or secondary alcohol having 8 to 25 carbon atoms, and is specifically used as a higher alcohol. , Octyl alcohol, decyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, oleyl alcohol, behenyl alcohol and other primary alcohols, 2-dodecanol, 2-tetradecanol, 2-hexadecanol, 2-octyldodeca Examples thereof include secondary alcohols such as Noll, natural alcohols such as coconut oil reduced alcohol, beef fat reduced alcohol, and McCaw alcohol. Further, the polyoxyethylene alkylaryl ether is produced by adding 1 to 200 mol of ethylene oxide to a phenol in which an alkyl group having 1 to 20 carbon atoms is substituted, and is specifically used as an alkylphenol. Examples thereof include dodecylphenol, octylphenol, octylcresol and cumylphenol.

Examples of the anionic surfactant include alkyl sulfates such as sodium dodecyl sulfate, potassium dodecyl sulfate, and ammonium dodecyl sulfate; sodium dodecyl polyglycol ether sulfate; sodium sulfolicynote; alkali metal salts of sulfonated paraffin, and sulfonated paraffin. Alkyl sulfonates such as ammonium salts of: sodium laurate, triethanolamine oleate, triethanolamine aviate, sodium laurate, potassium laurate, coconut oil soap, sodium myristate, sodium stearate, sodium palmitate, sodium oleate , Fatty acid salts such as potassium oleate; alkylaryl sulfonates such as sodium benzene sulfonate, alkali metal sulfate of alkaliphenol hydroxyethylene; high alkyl naphthalene sulfonate; naphthalene sulfonate formarin condensate; dialkyl sulfosuccinate; polyoxyethylene alkyl Sulfate salt; polyoxyethylene alkylaryl sulfate salt and the like can be mentioned.

A chain extender can be used to produce the anionic water-based polyurethane resin. As the chain extender, a commonly used chain extender is used, and examples thereof include low molecular weight polyol compounds having an average molecular weight of less than 200 and low molecular weight polyamine compounds.

Examples of the chain extender include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, and 2,2-. Polyols such as dimethyl-1,3-propanediol, 3-methylpentanediol, dimethylolpropionic acid, trimethylolpropane, pentaerythritol, ethylenediamine, propylenediamine, hexamethylenediamine, tolylenediamine, xylylenediamine, diaminodiphenylamine , Diaminocyclohexylmethane, piperazine, 2-methylpiperazine, isophoronediamine, melamine, dihydrazide succinate, dihydrazide adipate, dihydrazide phthalate and other amines and water. These chain extenders can be used alone or in combination of several types, and the amount used depends on the molecular weight of the target anionic aqueous polyurethane resin, but is usually used for NCO in the prepolymer. The active hydrogen that reacts with the reaction is used in an equivalent of 0.1 to 2 times, preferably 0.5 to 0.9 times. If the active hydrogen of the chain extender is less than 0.1 times equivalent, the molecular weight becomes too small, and if it is used in excess of 2 times equivalent, an unreacted chain extender remains, which deteriorates the physical characteristics of the obtained product. There is a risk that it will end up. Further, when a part of the trifunctional or higher functional low molecular weight polyol or low molecular weight polyamine is used among the chain extenders, an anionic aqueous polyurethane resin having excellent film physical characteristics may be obtained.

If necessary, a solvent is used to produce the prepolymer. The solvent used is preferably a solvent that is inert to the reaction and has a high affinity for water, and examples thereof include acetone, methyl ethyl ketone, dioxane, tetrahydrofuran, and N-methyl-2-pyrrolidone. These solvents are usually used in an amount of preferably 3 to 100% by mass based on the total amount of the above raw materials used for producing the prepolymer. Among these solvents, it is preferable that the solvent having a boiling point of 100 ° C. or lower is distilled off under reduced pressure after prepolymer synthesis.

As described above, it is well known that anionic water-based polyurethane resins are produced from these raw materials, and the order of charging these raw materials can be appropriately changed, or the raw materials can be separately charged.

The anionic aqueous polyurethane resin thus obtained is usually prepared so that the resin solid content is 30 to 50% by mass with respect to the entire emulsion. If the resin solid content is less than 30% by mass, the physical properties of the obtained film are deteriorated, the drying time is lengthened, sufficient mechanical strength cannot be obtained, and if it exceeds 50% by mass, the viscosity of the resin becomes high and uniform. I can't get a good film.

[Polycarbodiimide cross-linking agent (X)]
The polycarbodiimide cross-linking agent (X) used in the present invention is represented by the above general formula (1), forms a cross-linked structure with the above-mentioned carboxyl group-containing aqueous resin, and has strength, water resistance, and durability of the coating film of the aqueous resin. And so on.

In the above general formula (1), R ² represents a divalent residue obtained by removing the isocyanate group from the diisocyanate compound. Examples of the diisocyanate compound include an aromatic diisocyanate compound, an aliphatic diisocyanate compound, an alicyclic diisocyanate compound, a heterocyclic diisocyanate compound, and an aromatic aliphatic diisocyanate. Specifically, 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 1,3-phenylenediisocyanate, 1,4-phenylenediocyanate, 2,4-triisocyanate. Range isocyanate, 2,6-tolylene diisocyanate, mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, hexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, dicyclohexyl Examples thereof include methane-4,4'-diisocyanate, methylcyclohexanediisocyanate, tetramethylxylylene diisocyanate, and 2,5 (2,6) -bis (isocyanatomethyl) bicyclo [2.2.1] heptane. Among these, dicyclohexylmethane-4,4'-diisocyanate and tetramethylxylylene diisocyanate are preferable and easily available from the viewpoint of ease of synthesis of the polycarbodiimide cross-linking agent and storage stability of the synthesized polycarbodiimide cross-linking agent. From the viewpoint, dicyclohexylmethane-4,4'-diisocyanate is more preferable.

In the above general formula (1), R ¹ represents a residue obtained by removing a functional group capable of reacting with isocyanate from a hydrophilic compound having a functional group capable of reacting with isocyanate. The hydrophilic compound is preferably at least one selected from the group consisting of the following general formulas (2), (3), (4), and (5), and is water of the polycarbodiimide cross-linking agent (X). Alternatively, from the viewpoint of improving the solubility or dispersibility in a hydrophilic solvent, at least one selected from the group consisting of the following general formulas (2) and (3) is more preferable, and the following general formula (2) is used. It is more preferable to have.

R ⁴ O- (CH _2- CHR ^5- O) _p- H (2)

In the formula, R ⁴ is an alkyl group having 1 to ^{4 carbon atoms, and R 5} is a hydrogen atom or a methyl group. p is an integer of 4 to 30. Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, and a t-butyl group. A methyl group is preferable as ^{R 4} , and a hydrogen atom is preferable as ^{R 5.} p is an integer of 4 to 30, and from the viewpoint of improving the affinity between the polycarbodiimide cross-linking agent (X) and the carboxyl group-containing aqueous resin, an integer of 7 to 25 is preferable, and an integer of 8 to 20 is more preferable.

(R ⁶ ) _2- N-R ^7- OH (3)

In the formula, R ⁶ is an alkyl group having 1 to ^{6 carbon atoms, and R 7} is an alkylene group having 1 to 10 carbon atoms or a polyoxyalkylene group. ^{Examples of the alkyl group having 1 to 6} carbon atoms of R 6 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a t-butyl group, and an n-. Examples thereof include a pentyl group, an n-hexyl group and a cyclohexyl group. Of these, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an s-butyl group, an isobutyl group, and a t-butyl group are preferable. Examples of the alkylene group having 1 to 10 carbon atoms of R ⁷ include a methylene group, an ethylene group, a propylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, an octamethylene group, a nonamethylene group, and a decamethylene group. The group etc. can be mentioned. The hydrogen atom of the alkylene group may be substituted with a monovalent hydrocarbon group such as a methyl group. As R ⁷ , an ethylene group, a propylene group, a tetramethylene group, and a pentamethylene group are preferable.

(R ⁸ ) _2- N-R ^9- NH ₂ (4)

In the formula, R ⁸ is an alkyl group having 1 to 6 carbon atoms, and R ⁹ is an alkylene group having 1 to 10 carbon atoms or a polyoxyalkylene group. Examples of the alkyl group having 1 to 6 carbon atoms of R ^{8 include the same group as R 6} described above. Among them, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an s-butyl group and an isobutyl group. , And t-butyl groups are preferred. Examples of the alkylene group having 1 to 10 carbon atoms of R ⁹ include the same groups as those of ^{R 7.} As R ⁹ , an ethylene group, a propylene group, a tetramethylene group, and a pentamethylene group are preferable.

HO-R ^10- SO ₃ M (5)

In the formula, R ¹⁰ is an alkylene group having 1 to 10 carbon atoms, and M is an alkali metal such as Na or K. Examples of the alkylene group having 1 to ¹⁰ carbon atoms of R 10 include the same groups as those of ^{R 7.} Of these, a methylene group and an ethylene group are preferable.

In the general formula (1), R ³ represents a divalent residue obtained by removing a hydroxyl group from a glycol compound. The glycol compound shall be at least one selected from the group consisting of ethylene glycol, propylene glycol, 1,4-butanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, polyethylene glycol, and polypropylene glycol. Is preferable, and at least one selected from the group consisting of ethylene glycol, 1,4-butanediol, diethylene glycol, triethylene glycol, and polyethylene glycol is more preferable. The weight average molecular weight (Mw) of polyethylene glycol and polypropylene glycol is preferably 2,000 or less from the viewpoint of facilitating dissolution or dispersion in water or a hydrophilic solvent.

In the general formula (1), X represents a group formed by the reaction of the hydrophilic compound with the diisocyanate compound. For example, when the hydrophilic compound has the general formula (2), (3), or (5), X is a group represented by the following general formula (6), and the hydrophilic compound is the general formula. In the case of the formula (4), X is a group represented by the following general formula (7).

Further, in the general formula (1), n1 represents a number of 1 to 10, preferably a number of 1 to 5, and n2 represents a number of 1 to 10, preferably a number of 1 to 5. m represents a number from 1 to 5, preferably a number from 1 to 2.

The polycarbodiimide cross-linking agent (X) is preferably used by being dissolved or dispersed in at least one selected from water and a hydrophilic solvent.

The equivalent ratio of the carbodiimide group of the polycarbodiimide cross-linking agent (X) to the carboxyl group of the carboxyl group-containing aqueous resin is preferably 0.1 to 1.2. When it is 0.1 or more, the effect of adding the carbodiimide cross-linking agent (X) can be obtained, and when it is 1.2 or less, the carbodiimide cross-linking agent (X) does not remain excessively and the carbodiimide cross-linking agent (X) is not excessively left. ) Remains excessively, which can suppress the deterioration of performance.

The aqueous polyurethane resin composition for a thin film body of the present invention preferably further contains at least one selected from water and a hydrophilic solvent.

Examples of the hydrophilic solvent include polyalkylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, and dipropylene glycol monomethyl ether. Ethers; Polyalkylene glycol dialkyl ethers such as diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, dipropylene glycol dimethyl ether; ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol Polyalkylene glycol monoalkyl ether acetates such as monobutyl ether acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate; polyalkylene glycol diacetates such as ethylene glycol diacetate and propylene glycol diacetate; ethylene glycol monophenyl ether , Polyalkylene glycol monophenyl ethers such as propylene glycol monophenyl ethers; monoalcohols such as propanol, butanol, hexanol, octanol and the like.

Further, in the aqueous polyurethane resin composition for a thin film body of the present invention, if necessary, additives such as pigments, fillers, leveling agents, dispersants, ultraviolet absorbers, antioxidants, flame retardants, and colorants are added. It can be appropriately blended.

The aqueous polyurethane resin composition for a thin film body of the present invention has excellent storage stability, an increase in viscosity, and a small decrease in tensile strength of a cured product of the resin composition before and after storage, so that it can be used for dipping molding. ..

The aqueous polyurethane resin composition for a thin film body of the present invention has a viscosity of preferably 20 to 200 mPa · s, more preferably 20 to 80 mPa · s. If the viscosity of the water-based polyurethane emulsion used is too high, the liquid surface tends to dry and the produced film tends to be non-uniform, which is not preferable.

[Aqueous polyurethane resin composition for thin film body]
The water-based polyurethane resin composition for thin films of the present invention contains 100% self-emulsifying anionic water-based polyurethane emulsion having an average particle size of less than 0.1 μm, a nonionic surfactant of 0.05 to 2.5% by mass, and a carbodiimide crosslink. 1.6 to 5.2% by mass of the agent was added with stirring at 200 rpm.

That is, the self-emulsifying anionic aqueous polyurethane emulsion, the nonionic surfactant, and the carbodiimide cross-linking agent were mixed in this order with stirring to obtain an aqueous polyurethane resin composition for a thin film body.

[Thin film body]
The thin film body of the present invention was molded using the above-mentioned aqueous polyurethane resin composition for a thin film body. Examples of the thin film include a medical probe cover, an endoscopic camera cover, a finger cot, gloves, and a condom.

For example, the manufacture of condoms will be described.

Two dipping tanks containing the composition mixed above are prepared, a glass mold is dipped in the first tank, dried at 70 to 90 ° C. for 10 to 20 minutes, and cooled.

This operation is repeated twice, after which a mouth-wound portion is prepared, irradiated with far infrared rays at 150 to 200 ° C., and finally dried.

Then, after swelling with warm water at 40 to 70 ° C., it is peeled from the mold.

As the powder treatment, the powder was submerged in a dispersed liquid, dehydrated, and dried at 90 ° C. for 1 hour.

[transparency]

Haze meter cloudiness measurement (JIS, ASTM, ISO standard compliant) was performed.

In Examples, a product was prepared using a self-emulsifying anionic aqueous polyurethane emulsion having an average particle size of less than 0.1 μm.

Comparative Examples 1 to 4 targeted products using materials having an average particle size of more than 0.1 μm.

From the results in Table 1, the example product has an advantage of high transparency.

Similarly, when a cover for an endoscopic camera or the like is used, the sharpness of the image can be maintained.

[Permanent growth]

PS: Permanent growth (%)
l ₀ : Distance between marked lines (mm)
l ₁ : Length between marked lines (mm) after shrinking and leaving for a specified time
A dumbbell-shaped No. 2 piece based on JIS K6251: 2010 was used as a test piece.

The test piece to be measured was marked with a marker. The distance between the marked lines was set to 20 mm.

It was stretched to 300% at a speed of 200 ± 20 mm / min and held for 10 minutes.

The test piece stretched using a strograph was rapidly contracted without rebounding, and allowed to stand for 10 minutes in an atmosphere of 20 to 30 ° C.

Permanent elongation was calculated based on equation (8).

Therefore, from the results in Table 2, in the example product, the thin film body can be easily and smoothly attached.

Similarly, when it is used as a cover for an endoscopic camera or the like, it can be easily and smoothly attached.

[Unwinding]

The load when the condom was unwound was measured using a special ring.

Therefore, from the results in Table 3, the example product can be easily and smoothly mounted.

[Homogeneity]
The average thickness, vertical variation, and circumferential variation of the Example product and Comparative Examples 1 and 2 were measured.

Example: Average thickness 0.028 mm, vertical variation 7.4%, circumferential variation 7.7%
Comparative Example 1: Average thickness 0.030 mm, vertical variation 19.3%, circumferential variation 19.5%
Comparative Example 2: Average thickness 0.027 mm, vertical variation 19.9%, circumferential variation 7.3%

Therefore, from the results in Table 3, in the example product, the thin film body can be easily and smoothly attached.

Similarly, when it is used as a cover for an endoscopic camera or the like, it can be easily and smoothly attached.

[Allergy]
The polyurethane film of the example of the present invention is a synthetic rubber, and there is no problem of type I allergy derived from protein and type IV allergy derived from vulcanization accelerator.

Claims (8)

An aqueous polyurethane resin composition for a thin film body containing an anionic aqueous polyurethane resin and a carbodiimide cross-linking agent (X) represented by the following formula (1).

(In the formula, R ¹ represents a residue obtained by removing a functional group capable of reacting with isocyanate from a hydrophilic compound having a functional group capable of reacting with isocyanate, and R ² represents a divalent residue obtained by removing an isocyanate group from a diisocyanate compound. It represents a group, R ³ represents a divalent residue obtained by removing a hydroxyl group from a glycol compound, X represents a group formed by the reaction of the hydrophilic compound with the diisocyanate compound, and n1 represents a number of 1 to 10. , N2 represents a number from 1 to 10, m represents a number from 1 to 5. The plurality of R ¹ and R ² may be the same or different, respectively.) The aqueous polyurethane resin composition for a thin film according to claim 1.
The glycol compound is at least one selected from the group consisting of ethylene glycol, propylene glycol, 1,4-butanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, polyethylene glycol, and polypropylene glycol.
A water-based polyurethane resin composition for a thin film body. The aqueous polyurethane resin composition for a thin film according to claim 1 or 2.
The diisocyanate compound is dicyclohexylmethane-4,4'-diisocyanate.
A water-based polyurethane resin composition for a thin film body. The aqueous polyurethane resin composition for a thin film according to any one of claims 1 to 3.
An aqueous polyurethane resin composition for a thin film body, wherein the hydrophilic compound is at least one selected from the group consisting of the following general formulas (2), (3), (4), and (5).
R ⁴ O- (CH _2- CHR ^5- O) _p- H (2)
(In the formula, R ⁴ is an alkyl group having 1 to ^{4 carbon atoms, R 5} is a hydrogen atom or a methyl group. P is an integer of 4 to 30.)
(R ⁶ ) _2- N-R ^7- OH (3)
(In the formula, R ⁶ is an alkyl group having 1 to ^{6 carbon atoms, and R 7} is an alkylene group having 1 to 10 carbon atoms or a polyoxyalkylene group.)
(R ⁸ ) _2- N-R ^9- NH ₂ (4)
(In the formula, R ⁸ is an alkyl group having 1 to 6 carbon atoms, and R ⁹ is an alkylene group having 1 to 10 carbon atoms or a polyoxyalkylene group.)
HO-R ^10- SO ₃ M (5)
(In the formula, R ¹⁰ is an alkylene group having 1 to 10 carbon atoms, and M is an alkali metal such as Na or K.) The aqueous polyurethane resin composition for a thin film according to any one of claims 1 to 4.
Containing at least one selected from water and hydrophilic solvents,
A water-based polyurethane resin composition for a thin film body. The aqueous polyurethane resin composition for a thin film according to any one of claims 1 to 5.
The equivalent ratio of the carbodiimide group of the carbodiimide cross-linking agent (X) to the carboxyl group of the carboxyl group-containing aqueous resin is 0.1 to 1.2.
A water-based polyurethane resin composition for a thin film body. The aqueous polyurethane resin composition for a thin film according to any one of claims 1 to 6.
A thin film formed by using the aqueous polyurethane resin composition for a thin film was prepared.
A thin film body characterized by that. The aqueous polyurethane resin composition for a thin film according to any one of claims 1 to 6.
The mold is immersed in the aqueous polyurethane resin composition for a thin film body, dried, and then peeled off.
A method for producing a thin film body.