JPH0796601B2 - Non-porous film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a non-porous film using a polyurethane resin suitable as a moisture-permeable film material. More specifically, the present invention relates to a non-porous film formed by forming a polyurethane resin that does not turn yellow due to light, NOx gas and the like, has a small swell when absorbing water, and gives a film having excellent moisture permeability.

[Conventional technology]

It is well known that the introduction of polyethylene glycol into the polyol component is effective as a method for improving the moisture permeability of the polyurethane resin (Journal of App
lied Polymer Science, Vol. 16, 2105-2114, 1972). However, when the content of polyethylene glycol in the polyol component is increased in order to obtain good moisture permeability, swelling at the time of water absorption is remarkably increased and mechanical properties are inferior.

[Problems to be Solved by the Invention]

It is known that a moisture-permeable waterproof cloth having high moisture permeability can be obtained by making a polyurethane film porous by wet film formation.
However, when the transparency and strength of the film are required, or for medical and sanitary materials where the permeation of various bacteria and dirt is disliked, a porous film material is often desired. Heretofore, it has been difficult to obtain a polyurethane resin suitable for such applications, which has a high moisture permeability, a small swelling upon absorption of water, and a balance with practical physical properties.

[Object of the Invention]

The present invention is to provide a non-porous film that is non-porous and excellent in moisture permeability, has a small dimensional increase due to swelling even when absorbing water, and has no yellowing due to light, NOx gas, etc. And

Furthermore, the present invention has sufficient moisture permeability with a non-porous structure having no holes, pores, and discontinuous cross sections, and the adhesiveness is impaired even when it is applied to a bent portion or a curved portion such as a joint of a human body. It is intended to provide a membranous material for medical use which is flexible and has excellent physical properties.

[Means for Solving the Problems]

That is, the present invention has an ethylene oxide unit of 20-80
A random copolymer of tetrahydrofuran and ethylene oxide having a weight average content of 800 to 3000 in weight% is reacted with an alicyclic diisocyanate, the chain is extended with an alicyclic diamine, and the resulting polyurethane resin is formed into a film. The non-porous film is

The above-mentioned ethylene oxide unit in the present invention is a ratio of ethylene oxide to tetrahydrofuran and ethylene oxide expressed as a weight percentage.

The polyurethane resin in the present invention essentially comprises a random copolymer of tetrahydrofuran (hereinafter abbreviated as THF) and ethylene oxide (hereinafter abbreviated as EO) as a polyol component. This copolymer is water, ethylene glycol, 1,
THF using a short-chain diol such as 4-butanediol as an initiator
It is synthesized by ring-opening copolymerization of a mixture of EO with EO in the presence of a Lewis acid catalyst such as boron trifluoride ether complex salt.

The content of the EO unit in the random copolymer of THF and EO is 20 to 80% by weight, and preferably 30 to 70% by weight, in order to reduce swelling and deterioration of physical properties when absorbing water in the case of polyurethane. Is. A random copolymer of THF and EO having a number average molecular weight of 800 to 3000 is used. When the number average molecular weight is less than 800, the polyurethane film is hard, and when it is more than 3000, the tackiness is large and swelling due to water absorption is also increased. The number average molecular weight of 1,000 to 2,500 is preferable for obtaining the best film properties.

If necessary, a random copolymer of THF and EO may be mixed with polytetramethylene ether glycol (hereinafter abbreviated as PTMG) before use. In this case, the number average molecular weight of PTGM to be added is 800 to 3000, the number average molecular weight of the polyol mixture is 800 to 3000, and 1000 to 2500 is required to obtain a polyurethane film having a better balance of physical properties. preferable.

It should be noted that the random copolymer of THF and EO described above does not deviate from the intention of the present invention even if a partial block copolymer structure produced during polymerization is partially contained in the polyol chain.

As a copolymer of THF and EO, in addition to the above, EO is added to PTMG obtained by ring-opening polymerization of THF, or THF is added to polyethylene glycol (hereinafter abbreviated as PEG) obtained by ring-opening polymerization of EO. Block copolymers can also be obtained, but polyurethanes using these block copolymers can be incorporated into PTMG by including a long hydrophilic homopolymer chain of EO in the structure.
Similar to the case of using PEG mixed, swelling due to water absorption tends to remarkably increase as the EO content in the total amount of polyurethane increases, which is a practical problem.

When the above-mentioned random copolymer of THF and EO is used for the polyol component of polyurethane, surprisingly, the water absorption rate increases due to the increase of EO units compared to the block copolymer of THF and EO or the combined system of PTMG and PEG. It has been found that although it is small, it exhibits high moisture permeability.

To obtain the polyurethane resin aimed at by the present invention, an excess equivalent amount of an alicyclic diisocyanate is reacted with the above-mentioned specific polyol at 70 to 120 ° C. to obtain a urethane prepolymer having an isocyanate group at the end, and then the organic solvent is used in an organic solvent. 20 ~
Take the method of chain extension with alicyclic diamine at 40 ° C.

Here, the equivalent ratio of the alicyclic diisocyanate and the polyol in the urethane prepolymer is usually 1.5 to 4: 1, but in order to combine good physical properties and moisture permeability, it may be 1/8 to 3.2: 1. preferable.

Examples of the alicyclic diisocyanate used in the present invention include isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1,4-cyclohexylene diisocyanate, and hydrogenated products of tolylene diisocyanate. These are usually used alone, but two or more kinds may be used in combination. Of these, 4,4'-dicyclohexylmethane diisocyanate is most preferable from the viewpoint of the balance between mechanical properties and moisture permeability of the obtained film.

When an aliphatic diisocyanate such as hexamethylene diisocyanate is used in place of the alicyclic diisocyanate, a non-yellowing type is obtained, but the mechanical properties and heat resistance are poor, and when an aromatic diisocyanate is used, the physical properties are good. Is also not preferable because it yellows significantly due to light and NOx gas.

Examples of the alicyclic diisocyanate used as the chain extender in the present invention include isophoronediamine, 4,4'-dicyclohexylmethanediamine, 3,3'-dimethyl-4,4'-dicyclohexylmethanediamine, and 1,4-cyclohexylenediamine. Can be given. These may be used alone or in combination of two or more.

The above-mentioned alicyclic diamine is suitable from the viewpoint of stability of polyurethane solution and physical properties of the film, and if an aliphatic diamine such as ethylene azimine is used instead of these, the stability of the polyurethane solution is poor and, depending on the case, May be gelled. Further, aromatic diamines are not preferable because they are colored by oxidation. Particularly, isophoronediamine is particularly preferable from the viewpoint of solution stability.

As the organic solvent used for polyurethane synthesis in the present invention, a solvent having a strong dissolving power such as dimethylformamide, dimethylacetamide, and dimethylsulfoxide is suitable.
These are alone or aromatic solvents such as toluene and xylene, ketone solvents such as methyl ethyl ketone, acetone and cyclohexanone, acetic ester solvents such as ethyl acetate and butyl acetate, chlorine solvents such as dichloroethane, tetrahydrofuran, ethers such as dioxane. It is also possible to use one type or a mixture of two or more types selected from system solvents and alcohol solvents such as methanol and isopropanol.

The polyurethane resin obtained as described above preferably contains 15 to 60% by weight of ethylene oxide units in the total amount of polyurethane, and when the ethylene oxide units are less than 15% by weight, the moisture permeability of the film is insufficient, and 60 If it exceeds 5% by weight, dimensional change due to swelling at the time of water absorption and deterioration of physical properties are large, which is not preferable.

In the present invention, a catalyst which is usually used for accelerating the urethanization reaction, such as a tertiary amine such as triethylenediamine or an organic tin compound such as dibutyltin dilaurate, may be present in the present invention, if necessary.

Furthermore, when the polyurethane resin of the present invention is applied to a breathable waterproof cloth or the like, a hindered phenol-based antioxidant, a benzophenone-based or benzotriazole-based UV absorber, a hindered amine-based antioxidant for the purpose of improving durability of mechanical properties. One or more UV stabilizers may be contained in advance. In this case, each additive is added in an amount of 0.05 to 3% by weight with respect to the polyurethane solid content, but 0.2 to 1% by weight is preferable in order to obtain a good effect with a small amount. In the alicyclic diisocyanate-based polyurethane of the present invention, the hindered amine-based UV stabilizer is particularly effective, and even if added alone, it is possible to reduce the deterioration of physical properties even in the case of photodegradation and hydrolysis.

If necessary, an inorganic filler, a colorant, etc. may be added to the polyurethane resin of the present invention.

With respect to the film-forming method, it is known that a polyurethane film having high moisture permeability can be obtained by porosification. As a method therefor, (1) a polyurethane resin solution is applied onto a support and a solvent or other solvent is applied in a coagulation bath. Wet film-forming method for extracting soluble substances (2) A method in which a water-in-oil emulsion of a polyurethane resin is applied on a support and dried by heating to obtain a porous film. However, the porous membranes obtained by these methods are poor in strength, elongation, and durability when the membranes are used alone, require some kind of support, and have the drawback that the pores are blocked by juice or dirt and the moisture permeability is gradually lowered. Have.

Further, in the production of a porous membrane, the moisture permeability is likely to vary due to the difference in the pore diameter and the distribution of the pores, and delicate control of the production conditions is required in order to express a certain performance with good reproducibility.

Since the polyurethane film of the present invention is a non-porous film, it is inferior to the porous film in terms of moisture permeability. In order to obtain a non-porous film from a polyurethane resin solution, it is possible to obtain stable moisture permeability with good reproducibility by applying this solution to a support or release paper and drying it by heating to dryness. A product having sufficient strength, elongation and durability can be obtained.
Therefore, it is extremely useful as a medical adhesive film, a sanitary material, and other moisture-permeable materials that do not want to permeate foreign matter.

The support used for dry film formation is not particularly limited, but polyethylene or polypropylene film, release paper or cloth coated with a fluorine-based or silicone-based release agent, or the like is used.

The moisture permeability of the sheet material of the present invention is inversely related to the thickness of the film, and it is desirable to use a release paper having a uniform thickness. The coating method is not particularly limited, but a knife coater,
Any of the roll coaters can be used. The drying temperature can be arbitrarily set depending on the ability of the dryer, but it is necessary to select a temperature range in which insufficient drying or rapid desolvation does not occur. It is preferably in the range of 60 to 130 ° C.

The thickness of the formed film is usually 10 to 200 μm, preferably 1
It is 0 to 100 μm. The film of the present invention is characterized in that the moisture permeability is less dependent on the film thickness than other urethane-based films. If it is 10 μm or less, pinholes are likely to be formed during coating, and the film tends to be blocked, making it difficult to handle. If it is 100 μm or more, sufficient moisture permeability cannot be obtained.

The non-porous film of the present invention has a water vapor transmission rate of 10 to 100 μm.
1,000g / m ² · 24hr or more, preferably 1,500
It has g / m ² · 24hr or more (measured by JIS Z0208) and has high moisture permeability. When the amount is less than this, it is not preferable since it causes stuffiness and gives discomfort when it is applied to the skin as an adhesive film. It has a 100% modulus of 20 kg / cm ² or more, preferably 30 kg / cm ² or more, and has high flexibility. 20 kg / c
At m ² or less, the tackiness of the film is large, and both films are likely to cause blocking. If it is 80 kg / cm ² or more, the flexibility tends to be poor and the moisture permeability tends to decrease.

When the non-porous film of the present invention is used as a medical film or tape, an adhesive for adhering to the skin surface is applied to one surface of the film. As such an adhesive, various conventionally known adhesives can be used, for example,
Examples thereof include natural rubber, butyl rubber, styrene-butadiene rubber, polyisobutylene rubber, acrylic polymers and polyurethane-based adhesives, and polyurethane-based adhesives are preferable. Adhesive coating thickness is usually 10-50 μm
It is a degree.

〔Example〕

Hereinafter, the present invention will be described by way of examples, but the present invention is not limited to the contents of the examples.

<Production Examples 1 to 4 of THF / EO random copolymers> According to the formulations shown in Table-1, ethylene glycol was used as an initiator and BF ₃ · ethyl ether complex salt was used as an acid catalyst in an autoclave, and THF and EO were mixed under normal pressure. Random copolymerization at 30 ° C. After the polymerization, the acid catalyst in the product was neutralized with an alkali, the precipitate was filtered, and dried at 100 ° C. by blowing dry nitrogen.

The obtained four kinds of THF / EO random copolymers of A, B, C and D (hereinafter referred to as polyols) are all colorless and transparent liquids, and the number average molecular weight and EO content are as shown in Table-1. Met.

The number average molecular weight was calculated by OH value measurement, and the EO content was calculated from the charged amount.

Examples 1 to 3 a) Preparation of Polyurethane Solution Using the polyols A, B and C shown in Table-1, 4,4'-dicyclohexylmethane diisocyanate and each polyol were prepared under dry nitrogen according to the formulation shown in Table-2. After reacting in a flask at 100 ° C for 6 hours to form a urethane prepolymer having an isocyanate group at the terminal, isophoronediamine is used as a chain extender in a dimethylformamide solvent and a chain extension reaction is carried out for 2 hours while maintaining the temperature at 30 ° C. A colorless transparent viscous polyurethane solution having a polyurethane solid content of 20 wt% was obtained. The viscosities at these temperatures of 25 ° C are 35,0
It was 00cps, 20,000cps, 15,000cps.

b) Preparation of polyurethane film The above-mentioned polyurethane solution was poured onto a glass plate provided with a spacer, stretched with a glass rod to apply a uniform thickness, and then dried at 80 ° C for a whole day and night to obtain a colorless transparent polyurethane dry film. At this time, the thickness of the film was adjusted by a spacer so that it was about 50 μm. The obtained film was aged in a constant temperature and humidity chamber at 23 ° C. and 60% RH for performance test.

c) Performance test of polyurethane film <Measurement of water absorption dimension increase rate> A 50 mm x 50 mm polyurethane film was immersed in 23 ° C water for 24 hours, and the water absorption dimension increase rate was calculated from the dimension measurement values before and after water absorption.

<Measurement of moisture vapor transmission rate> According to JIS Z-0208, the moisture vapor transmission rate of the film was determined by weight measurement using a moisture vapor transmission cup under the conditions of 40 ° C and 90% RH.

<Light resistance test> The light resistance of the polyurethane film was evaluated by observing the yellowing of the film and the mechanical properties by irradiating with ultraviolet light for 50 hours in an atmosphere of 63 ± 3 ° C with a fade meter according to JIS L0842.

<NOx resistance test> According to the method of JIS L0855, yellowing of the film was examined in a NOx gas atmosphere at a constant temperature of 23 ° C.

<Hydrolysis resistance test> The polyurethane film was evaluated by exposing it to an atmosphere of 70 ° C and 95% RH for 3 weeks and measuring the mechanical properties.

Example 4 To the polyurethane solution obtained in Example 2, as an additive, Tinuvin 144 (trade name, manufactured by Ciba-Geigy Co., Ltd., a bindered amine UV stabilizer) having the following structural formula was added in an amount of 0.5% by weight based on the solid polyurethane content. A polyurethane film was prepared in the same manner as described in No. 3 to 3, and the performance test was conducted.

The results are shown in Table-2. As compared with Example 2 in which TINUVIN 144 was not added, remarkable improvement was observed in the mechanical properties of the film due to photodegradation and hydrolysis.

Tinuvin 144: 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalonate bis (1,2,2,6,6-pentamethyl-4-piperidyl) Comparative Example 1 Polyol D containing 85% by weight of the EO unit obtained in Production Example-4 shown in Table 1 was used, and 370 parts by weight of this was prepared under the same conditions as in Example 4,4'-dicyclohexylmethane diisocyanate 96.9. By weight reaction, 33.1 parts by weight of isophoronediamine was added to dimethylformamide for chain extension to obtain a colorless transparent viscous solution having a polyurethane solid content of 25%.
The EO content in this polyurethane solid content was 63% by weight.

When a polyurethane film was prepared and a performance test was conducted in the same manner as in the example, the water vapor transmission rate showed a high value of 4800 g / m ² · 24 hr, but the water absorption dimension increase rate of the film was large at 15% and it was poor in practicality. .

Comparative Example 2 Polycaprolactone polyester polyol having a number average molecular weight of 820 (trade name: Praxel 208 manufactured by Daicel Chemical Co., Ltd.) 2
After reacting 862.7 parts by weight of 182.7 parts by weight of 4,4'-dicyclohexylmethane diisocyanate in a nitrogen atmosphere at 100 ° C for 6 hours, in cyclohexanone in the presence of 0.1 g of dibutyltin dilaurate, 1,4'-butanediol 31.3 Polyurethane solid content of 25 g
A wt.% Colorless transparent viscous liquid was obtained.

As a result of a performance test of the film using this polyurethane solution in the same manner as in the example, the water absorption dimension increase rate was almost 0, but the water vapor transmission rate was 800 g / m ² · 24 hr, which was an extremely low value.

Examples 5 to 6 Using the above-mentioned polyol B, according to the formulation shown in Table-3,
In the same manner as in Example 1, a polyurethane solution having a solid content concentration of 25% by weight (Example 5) and 20% by weight (Example 6) was obtained. The viscosities at these temperatures of 25 ° C are 20,000 cps, 23,0 and
It was 00 cps.

A polyurethane film is prepared in the same manner as in Example 1 below,
The performance was evaluated. The results are shown in Table-3. In addition, Table 3 also shows that of Example 2.

<Production Examples 5 to 6 of THF / EO block copolymerized polyol> PTMG850 (polytetramethylene ether glycol, number average molecular weight 850) which is a polymer of THF as an initiator in a glass reactor according to the formulation shown in Table 4 Using potassium hydroxide as a catalyst, 12.0 parts by weight is added to 500 parts by weight of polytetramethylene ether glycol (PTMG) and ethylene oxide (EO) in total, and ethylene oxide (EO) is added by blowing at normal pressure and 50 ° C. Polymerization, PTMG
Polyoxyethylene chain bound to both ends of 850 molecular chain T
HF / EO block copolymer polyol was produced.

The potassium hydroxide in the polymerization product was neutralized with phosphoric acid to remove the precipitate, and then dried nitrogen was blown at 100 ° C. to dehydrate it to obtain a polyurethane production raw material.

The obtained block copolymer polyols E and F were white wax at 20 ° C., and the number average molecular weight was as shown in Table 4.

Comparative Examples 3 to 6 Block copolymerized polyols E and F of Production Examples 5 and 6 shown in Table 4 above, and ordinary polytetramethylene ether glycol (PTMG) and polyethylene glycol (PE
Using the mixture of G), 4,4'-dicyclohexylmethane diisocyanate was reacted with each polyol according to the formulation shown in Table 5 under dry nitrogen in a flask at 100 ° C for 6 hours to obtain a urethane polymer having a terminal isocyanate group. .

Next, the chain extension reaction of the urethane prepolymer was carried out at 30 ° C. in dimethylformamide using isophorone diamine as a chain extender to obtain a colorless transparent viscous polyurethane solution having a solid content of 25%. The viscosity is as shown in Table-5.

Using these polyurethane solutions, a polyurethane film was prepared in the same manner as in Example 1, and the performance test of the film was conducted. The results are shown in Table-5.

(Function) The THF / EO random copolymer used for the polyol component in the present invention is made into polyurethane by using continuous chains of EO units having a large water absorption, which are relatively shortly separated by scattering of THF units. It is presumed that even though the water absorption of the resin is small, it exhibits high moisture permeability due to the hydrophilicity of the EO unit.

〔The invention's effect〕

According to the present invention, a non-porous film obtained by forming a polyurethane resin showing high moisture permeability, small swelling upon absorption of water, and having excellent durability against light, NOx gas, hydrolysis, etc. This is suitable as a breathable waterproof cloth, medical, hygiene material, and the like.

Further, the urethane-based film of the present invention has moisture permeability but is non-porous so as to prevent passage of bacteria and the like, allow skin respiration, and have elasticity, so that it is applied to any part of the human skin surface. However, there is no risk of skin swelling, itchiness, rash, peeling from the skin due to bending movement, or risk of infection, and comfortable and early treatment is possible.

Therefore, the non-porous film of the present invention is useful as a wound dressing material, a surgical tape, a surgical film and the like.

 ─────────────────────────────────────────────────── --Continued from the front page (56) Reference JP 61-155417 (JP, A) JP 60-206817 (JP, A) JP 59-108021 (JP, A) JP 57- 143318 (JP, A) JP-A-54-130699 (JP, A) JP-A-55-54321 (JP, A) JP-A-53-16796 (JP, A) JP-B-49-6558 (JP, B1) Japanese Patent Sho 48-29638 (JP, B1) Japanese Patent Sho 47-3986 (JP, B1)

Claims (11)

[Claims] 1. A random copolymer of tetrahydrofuran and ethylene oxide having an ethylene oxide unit content of 20 to 80% by weight and a number average molecular weight of 800 to 3000 is reacted with an alicyclic diisocyanate to form a chain with an alicyclic diamine. A non-porous film formed by extending and forming a polyurethane resin obtained. 2. The non-porous film according to claim 1, wherein the random copolymer contains 30 to 70% by weight of ethylene oxide units. 3. The non-porous film according to claim 1, wherein the random copolymer has a number average molecular weight of 1,00.
A non-porous film that is 0 to 2,500. 4. The non-porous film according to claim 1, wherein the alicyclic diisocyanate comprises isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1,4-cyclohexylene diisocyanate and tolylene diisocyanate. A non-porous film selected from the group consisting of hydrogenated products. 5. The non-porous film according to claim 4, wherein the alicyclic diisocyanate is 4,4′-dicyclohexylmethane diisocyanate. 6. The non-porous film according to claim 1, wherein the alicyclic diamine is isophoronediamine, 4,4'-dicyclohexylmethanediamine, 3,3'-
A non-porous film selected from the group consisting of dimethyl-4,4'-dicyclohexylmethanediamine and 1,4-cyclohexylenediamine. 7. The non-porous film according to claim 6, wherein the alicyclic diamine is isophorone diamine. 8. The non-porous film according to claim 1, wherein the film has a thickness of 10 to 100 μm. 9. The non-porous film according to claim 1, wherein the water vapor permeability of the film is 1,000 g / m ² · 24 hr or more. 10. The non-porous film according to claim 1, wherein the 100% modulus of the film is 20 kg / cm.
A non-porous film that is ³ or more. 11. The non-porous film according to claim 1, wherein the film has a thickness of 10 to 100 μm, a moisture permeability of 1,000 g / m ² · 24 hr or more, and a 100% modulus of 20 kg / cm ^3.
The above is a non-porous film.