JPH1135653A - Silk fibroin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tenacity silk fibroin-based material applicable to clothing, medical use, synthetic leather, adhesives, paints, inks, compounds, fiber treatment agents, agricultural sheets, fishing nets, fishing lines and the like. . SOLUTION: This is a silk fibroin-based composition comprising a hydrophilic polyisocyanate (A), silk fibroin (B), and an active hydrogen group-containing hydrophilic polymer (C) other than (B).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a silk fibroin-based composition. More specifically, it relates to a silk fibroin-based composition comprising a hydrophilic polyisocyanate, silk fibroin, and an active hydrogen group-containing polymer other than silk fibroin.

[0002]

2. Description of the Related Art Recently, researches on effective use of silk waste have been actively conducted. Silk fibroin obtained by regenerating silk waste is biocompatible, and it has been confirmed that the molded membrane shows a high oxygen permeability in a wet state equivalent to that of a commercially available contact lens. For this reason, silk fibroin is expected to be applied to medical materials. For example, Japanese Patent Application Laid-Open No. 1-2541
No. 64 discloses a wound protecting material using silk fibroin gel and a molding method thereof. However, silk fibroin films are generally brittle, and lack strength and other properties.
It was not practical.

[0003]

Accordingly, an object of the present invention is to provide a silk fibroin-based composition having excellent strength and durability.

[0004] To this end, the present inventors have conducted intensive studies and as a result, have found that a silk fibroin-based composition having a specific composition satisfies the above-mentioned problems, and have completed the present invention.

[0005]

That is, the present invention provides:
(1) A silk fibroin-based composition characterized by using a hydrophilic polyisocyanate (A), silk fibroin (B), and a hydrophilic polymer (C) containing an active hydrogen group other than (B).

According to the present invention, (2) the silk fibroin according to the above (1), wherein the polar groups of the hydrophilic polyisocyanate (A) and the active hydrogen group-containing hydrophilic polymer (C) are nonionic. It is a system composition.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION As the hydrophilic polyisocyanate (A) used in the present invention, a compound containing a hydrophilic group and an active hydrogen group (A) is added to a base polyisocyanate (A1).
Modified in 2). As (A2),
There is no particular limitation, and examples thereof include compounds containing any of a nonionic polar group, an anionic polar group, a cationic polar group, and an amphoteric polar group and containing an active hydrogen group. (A2) has one or more active hydrogen groups. In the present invention, they may be used alone or may contain different types of hydrophilic polar groups.

Examples of (A1) include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate,
2,4'-diphenylmethane diisocyanate, 2,
2'-diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, 1,4-naphthylene diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, o-xylylene diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, Tetramethylxylylene diisocyanate, 4,4'-diphenyl ether diisocyanate, 2-nitrodiphenyl-4,4'-diisocyanate, 2,2'-diphenylpropane-4,4'-diisocyanate, 3,3'-dimethyldiphenylmethane-4 Aromatic diisocyanates such as 4,4'-diisocyanate, 4,4'-diphenylpropane diisocyanate, 3,3'-dimethoxydiphenyl-4,4'-diisocyanate, tet Methylene diisocyanate, hexamethylene diisocyanate (referred to hereinafter as HDI),
Decamethylene diisocyanate, 2-methyl-1,5-
Aliphatic diisocyanates such as pentane diisocyanate, 3-methyl-1,5-pentane diisocyanate, lysine diisocyanate, isophorone diisocyanate,
There are alicyclic diisocyanates such as hydrogenated diphenylmethane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated tetramethyl xylylene diisocyanate, cyclohexyl diisocyanate, and mixtures of two or more of these. Further, a single product or a mixture of the above-mentioned organic diisocyanate, such as a urethane-modified product, an allophanate-modified product, a buret-modified product, a carbodiimide-modified product, a uretonimine-modified product, a uretdione-modified product, or an isocyanurate-modified product, can also be used. Further, polymeric isocyanates such as polyphenylene polymethylene polyisocyanate and crude tolylene diisocyanate can also be used. (A1) in (A) used in the present invention is preferably an aliphatic diisocyanate and a modified product thereof, and an alicyclic diisocyanate and a modified product thereof in consideration of the reactivity with water.

Specific examples of the hydrophilic group in (A2) include the following. Nonionic polar _{groups: -CH 2 CH 2 O -,} - OH anionic polar _{group: -SO 3 M, -OSO 3 M} , -COOM, -PO (OM)
₂ (M represents an alkali metal, organic tertiary amine, or quaternary ammonium ion) Cationic polar group:

(Equation 1) (R _{1 to} R ₃ each represent a monovalent hydrocarbon group which may be the same or different, and X ⁻ represents a monovalent anion.) Amphoteric polar group:

(Equation 2)

(Equation 3)

(Equation 4) (R in Formulas 2 to 4 represents a divalent hydrocarbon group.)

Considering the crosslinking reaction between the isocyanate group and the active hydrogen group, the polar group (A2) is preferably a nonionic polar group that hardly causes a side reaction. Note that a hydrophobic group such as a hydrocarbon group may be introduced into (A) in consideration of the pot life at the time of dispersion in water.

The isocyanate content of (A) is 10 to 5
0% by weight, preferably 15 to 45% by weight. Specific examples of (A) include AQUANATE 10 manufactured by Nippon Polyurethane Industry, in which a nonionic polar group is introduced into an HDI-modified polyisocyanate, and a hydrophobic group is further introduced as necessary.
0, 110, 200, 210 and the like.

The silk fibroin (B) in the present invention comprises:
Used in the state of silk fibroin solution. The solid content of the silk fibroin solution is 0.5 to 50% by weight, preferably 1 to 10% by weight. As silk fibroin solution,
A known so-called regenerated silk fibroin solution may be used.
Examples of the solvent for the silk fibroin solution include a copper-ethylenediamine aqueous solution, a copper hydroxide-ammonia aqueous solution (Schweizer reagent), a copper hydroxide-alkali-glycerin aqueous solution (Roe reagent), a lithium bromide aqueous solution, calcium, magnesium, and zinc hydrochlorides. An aqueous solution of nitrate or thiocyanate, an aqueous solution of sodium thiocyanate, or the like can be used. In consideration of cost, workability, and the like, the solvent is preferably a calcium or magnesium hydrochloride or a nitrate aqueous solution.

On the other hand, as silk fibroin as a solute, silk fiber waste generated in a raw silk process or a silk spinning process is refined by a known method using Marcel soap and / or soda ash to remove residual sericin. Use less than 1%. Such a silk fibroin solution in which the silk fibroin is dissolved may be used as it is, but in consideration of the reactivity with the isocyanate group, it is preferable to perform abasic / desalting treatment such as semipermeable membrane or electrodialysis.

The active hydrogen group-containing hydrophilic polymer (C) other than (B) used in the present invention is a polymer containing an anionic, cationic or nonionic polar group and an active hydrogen group. And a specific example of the polar group is a polar group that can be introduced into the above-mentioned hydrophilic polyisocyanate (A). Preferred in the present invention is a nonionic polar group and an active hydrogen group-containing polymer that hardly causes side reactions in consideration of the reactivity of isocyanate, such as polyvinyl alcohol, and the polyvinyl alcohol is partially saponified or acetalized. It is preferable that the residual hydroxyl groups be 10 to 90 mol% by the treatment.

In the present invention, various additives other than the above-mentioned components can be used. For example, catalysts, fillers, antioxidants, ultraviolet absorbers, plasticizers, dyes, pigments, lubricants, hydrolysis inhibitors, tackifiers, antiblocking agents, antifungal agents, antibacterial agents, flame retardants, antistatics Agent and the like.

The method of blending the silk fibroin composition of the present invention is not particularly limited. For example, (1) an aqueous solution of silk fibroin (B) mixed with an active hydrogen group-containing hydrophilic polymer (C) other than (B),
Mix a hydrophilic polyisocyanate. (2) First, an aqueous solution of silk fibroin (B) and an active hydrogen group-containing hydrophilic polymer (C) other than (B) are blended and mixed with the hydrophilic polyisocyanate (A). And the like. In addition, the hydrophilic polyisocyanate (A)
Workability is better when emulsified and dispersed in water in advance.

The ratio of each component at the time of blending is (B):
(C) = 10-90: 90-10% by weight, preferably (B) :( C) = 15-85: 85-15% by weight. When (B) is less than 10% by weight, biocompatibility is insufficient. When (B) exceeds 90% by weight,
Elongation is too small. The compounding ratio of (A) is
0.5 to 100 parts by weight of the total of (B) and (C)
20 parts by weight, preferably 1 to 10 parts by weight. (A)
Is less than the lower limit, the elongation of the molded product is insufficient. On the other hand, when the ratio exceeds the upper limit, the urea group bond increases in the molded product, so that the molded product tends to lack flexibility.

There is no particular limitation on the specific molding method when using the silk fibroin-based composition of the present invention, and a method according to the purpose can be selected. For example, the silk fibroin-based composition of the present invention may be coated, sprayed, cast-molded, injection-molded, cast, or spray-dried to form a powder. At this time, heating may be performed in order to promote a crosslinking reaction between the isocyanate group and the active hydrogen group. Further, it may be impregnated into a fibrous material or used as a component of various laminated materials.

[0019]

According to the present invention, it has become possible to provide a tough silk fibroin-based material. The silk fibroin-based composition of the present invention can be applied to clothing, medical use, synthetic leather, adhesives, paints, inks, compounds, fiber treatment agents and the like. Since silk fibroin is a natural polymer and has biodegradability, it can be expected to be applied to fields utilizing this property, for example, agricultural sheets, fishing nets, fishing lines, and the like.

[0020]

EXAMPLES The present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples. In Examples and Comparative Examples, “parts” were used.
Means "parts by weight", and "%" means "% by weight".

[Preparation of Silk Fibroin Aqueous Solution] Silk fiber waste is refined with a 0.5% soda ash aqueous solution, and
It was dissolved in an aqueous solution of calcium chloride. After filtering this solution, a 2% silk fibroin aqueous solution was obtained by abasic / desalting treatment by electrodialysis for 2 days. In addition, the residual sericin was less than 1%.

[Preparation of Film Cast Sample] Example 1 A 5% aqueous polyvinyl alcohol solution was mixed with a 2% aqueous silk fibroin solution to prepare a blend solution of silk fibroin / polyvinyl alcohol = 25/75 (%) in terms of solid content. . The conditions at the time of blending are 80 ° C. for 2 hours. Next, a hydrophilic polyisocyanate (trade name:
Aquanate 200, manufactured by Nippon Polyurethane Industry Co., Ltd.) in terms of solid content, blend solution / hydrophilic polyisocyanate =
100/5 (parts) were blended and mixed at a high speed to prepare a liquid for film casting. The obtained liquid was cast and vacuum dried at 50 ° C. for 20 hours to obtain a cast film sample of Example 1.

[Preparation of Film Cast Samples] Examples 2 and 3 In the same manner as in Example 1, with the formulation shown in Table 1,
3 cast film samples were obtained.

Comparative Examples 1 to 7 In the same manner as in Example 1, with the formulations shown in Table 1,
7 cast film samples were obtained. Table 1, Figures 1 and 2
Shows the cast sample and various measurement results.

[0025]

[Table 1]

In Table 1, SF: silk fibroin PVA: polyvinyl alcohol having a degree of saponification of about 88 mol% AQ: hydrophilic polyisocyanate (trade name: Aquanate 200, manufactured by Nippon Polyurethane Industry)

Conditions for measuring physical properties Measuring device: UTM-500 manufactured by Orientec Test piece: Dumbbell piece (parallel linear distance 35 mm × width 5 mm) Measurement humidity: 65% RH Measurement temperature: 20 ° C. Peeling speed: 10 mm / min Infrared absorbance analysis Measurement Apparatus: Fourier transform infrared spectrometer (FT-
IR-8000) Resolution: 1 cm ^-1 Number of integration: 64 times IRE: KRS-5 Permittivity Temperature Dispersion Measurement Measuring Equipment: RHEOLOGRAPH SO manufactured by Toyo Seiki Co., Ltd.
LID frequency: 10 Hz Heating rate: 5 ° C / min Temperature range: room temperature to 150 ° C

From Table 1, it was found that when a hydrophilic polyisocyanate was added to a silk fibroin (SF) / polyvinyl alcohol (PVA) blend system, the elongation characteristics were remarkably improved and the crystallinity was also improved. From FIG. 1, it was found that when polyvinyl alcohol was blended with silk fibroin, β-sheet formation of silk fibroin occurred. This change is preferable as a material since it leads to improvement in physical properties. From FIG. 2, the top peak of tan δ is shifted to the higher temperature side in the SF / PVA blend system than in each of the single systems. This indicates that the SF / PVA blend system has improved heat resistance as compared to the individual systems.

[Brief description of the drawings]

FIG. 1 shows FT-IR in Examples and Comparative Examples of the present invention.
It is a chart.

FIG. 2 is a dielectric constant temperature dispersion chart in Examples and Comparative Examples of the present invention.

[Explanation of symbols]

a: hydrophilic polyisocyanate (Aquanate 200) b: SF / PVA / AQ = 0/100/5 (weight ratio, solid content conversion) c: SF / PVA / AQ = 25/75/5 (weight ratio, solid) Min) d: SF / PVA / AQ = 50/50/5 (weight ratio, solid content conversion) e: SF / PVA / AQ = 75/25/5 (weight ratio, solid content conversion) f: SF / PVA / AQ = 100/0/5 (weight ratio, solid content conversion) SF: silk fibroin PVA: polyvinyl alcohol having a saponification degree of about 88 mol% AQ: hydrophilic polyisocyanate (trade name: Aquanate 200, manufactured by Nippon Polyurethane Industry) )

Claims (2)

[Claims] 1. A silk fibroin-based composition comprising a hydrophilic polyisocyanate (A), silk fibroin (B), and an active hydrogen group-containing hydrophilic polymer (C) other than (B). 2. The silk fibroin-based composition according to claim 1, wherein the polar groups of the hydrophilic polyisocyanate (A) and the active hydrogen group-containing hydrophilic polymer (C) are nonionic.