Slidable rubber material having an amino-modified interfacial modification layer, and method for producing said slidable rubber material

Abstract

A slidable rubber material that has an amino-modified interfacial layer that does not affect the compression set. Although the slidable rubber material includes a rubber component such as a butyl rubber or halogenated butyl rubber etc. having the low-compression set, which contains a vulcanization agent such as a nitrogen/sulfur compound or a vulcanizing auxiliary agent, the rubber part is coated with a silicone rubber layer. The slidable rubber material exhibits a slidability and resists the detachment or elution of fine particles from the coating layer. A rubber component and a vulcanization agent; an interfacial modification layer that coats the rubber part and an amino-modified silicone compound is incorporated with surface molecules of the rubber part; and a layer that coats the interfacial modification and contains solid fine particles, an addition-type or condensation-type silicone rubber in which the particles are dispersed, and a curing catalyst for silicone rubber.

Claims

1. A slidable rubber material, which has an amino-modified interfacial modification layer, comprising: a rubber part containing a rubber component selected from the group consisting of butyl rubber, halogenated butyl rubber and polychloroprene rubber, a filler, a vulcanization agent and a vulcanizing auxiliary agent; an interfacial modification layer which coats the rubber part and in which an amino-modified silicone compound is incorporated and/or reacted with surface molecules of the rubber part; and a coating layer which coats the interfacial modification layer and contains solid fine particles, an addition-type and/or condensation-type silicone rubber in which the solid fine particles are dispersed, and a curing catalyst for the silicone rubber, and a thickness of the coating layer is 5-30 μm.

2. The slidable rubber material according to claim 1, wherein the amino-modified silicone compound is an amino-modified silicone oil having an amino-substituent on any one of silicone-repeating-units and/or at a terminal; or an amino-modified silicone oil having an amino-substituent on any one of silicone-repeating-units and/or at a terminal while having a hydroxyl group or a protected hydroxyl group on any one of silicone-repeating-units and/or at a terminal.

3. The slidable rubber material according to claim 1, wherein the solid fine particles are silica particles and/or silicone particles.

4. The slidable rubber material according to claim 1, wherein an average particle size of the solid fine particles is 0.1-10 μm.

5. The slidable rubber material according to claim 1, wherein a part of the solid fine particles provides with an uneven surface on the coating layer.

6. The slidable rubber material according to claim 1, wherein the coating layer neither include nor hold a silicone oil inside and on an exposed surface thereof.

7. The slidable rubber material according to claim 1, wherein the filler is silica, talc, titanium oxide, carbon black, clay and/or calcium carbonate.

8. The slidable rubber material according to claim 1, wherein the vulcanization agent is a mercaptobenzimidazole derivative and/or a triazine dithiol derivative.

9. The slidable rubber material according to claim 1, wherein the vulcanizing auxiliary agent is an organic acid zinc salt.

10. The slidable rubber material according to claim 1, wherein the rubber part includes any one selected from the group consisting of; an acid-acceptor selected from magnesium oxide, zinc oxide, and natural or synthetic hydrotalcite, an alkoxysilane compound, and a softening agent selected from an organic resin, and a silicone oil or a paraffin oil.

11. The slidable rubber material according to claim 1, wherein the curing catalyst is a platinum catalyst.

12. The slidable rubber material according to claim 1, wherein the coating layer is provided over the interfacial modification layer directly or through a primer layer.

13. The slidable rubber material according to claim 1, wherein the slidable rubber material is used for medical purposes.

14. The slidable rubber material according to claim 1, wherein the slidable rubber material is a gasket of a syringe or of an injector.

15. A method for producing a slidable rubber material, which has an amino-modified interfacial modification layer, comprising: forming an interfacial modification layer, in which an amino-modified silicone compound is incorporated and/or reacted with surface molecules of a rubber part, by applying a composition containing the amino-modified silicone compound for forming the interfacial modification layer onto the rubber part containing a rubber component selected from the group consisting of butyl rubber, halogenated butyl rubber and polychloroprene rubber, a filler, a vulcanization agent and a vulcanizing auxiliary agent, and then, covering the interfacial modification layer through a coating layer having a thickness of 5-30 μm by applying a composition containing solid fine particles, an addition-type and/or condensation-type silicone rubber ingredients in which the solid fine particles are dispersed, and a curing catalyst for the silicone rubber.

Description

EMBODIMENTS

(1) The following is a detailed explanation of examples of the implementation of the present invention for medical gaskets made of slidable rubber materials. At first, adhesion strength was evaluated using their sheet shapes.

Example 1

(2) The composition for rubber parts was prepared to evaluate the adhesion strength.

(3) After stirring and mixing 100.00 parts by mass of chlorinated butyl rubber (JSR CHLOROBUTYL 1066: trade name, available from JSR Corporation) as a polymer component, 0.30 parts by mass of stearic acid (purified stearic acid 550V: trade name, available from KAO co., Ltd.), 0.30 parts by mass of zinc stearate (Zn-St (plant): trade name, available from NITTO Chemical Industry Co., Ltd.), and 5.00 parts by mass of paraffinic oil (DYANA PROCESS OIL PW-380: trade name, available from IDEMITSU KOSAN Co., Ltd.) as processing aid agents, 2.00 parts by mass of magnesium oxide (Kyowa Magu #30: trade name, available from Kyowa Chemical Industry Co., Ltd.) as an acid-acceptor, 0.30 parts by mass of carbon black (Asahi #35: trade name, available from Asahi Carbon Co., Ltd.) and 3.00 parts by mass of sulfuric acid method rutile-type titanium oxide (TIPAQUE R-630: trade name, available from Ishihara Sangyo Kaisha, Ltd.) as colorants, 60.00 mass % of talc (GH3: trade name, available from Hayashi Kasei Co., Ltd.) and 20.00 mass % of ultra-high molecular weight polyethylene (MIPELON XM-220: trade name, available from Mitsui Chemicals Inc.) as fillers, and 0.60 mass % of 3-mercaptopropyltrimethoxysilane (DOWSIL Z-6062 Silane: trade name, available from Dow-Toray Co., Ltd.) as an alkoxysilane compound with a sealed pressure kneader, to this kneaded mixture was added 0.70 parts by mass of 6-(dibutylamino)-1,3,5-triazine-2,4-dithiol (ZISNET DB: trade name, available from Sankyo Kasei Co., Ltd.) as a vulcanization agent and stirred and mixed with an open roll to obtain the composition for rubber parts.

(4) The composition for rubber parts was cut properly in an automatic machine to fill into a cavity of a vulcanization mold with an appropriate weight and shape, and the rubber raw material was pre-molded. This pre-molded rubber raw material was put into a rubber sheet-forming mold followed by press-heating in a vulcanization-molding press-machine at 180° C. for 10 min, and, after vulcanization and molding into a sheet shape of size 50×50×2 mm, the rubber sheet was obtained.

(5) The above rubber sheet was immersed in 0.6 weight % of an aqueous sodium carbonate solution and boiled for 90 min, thereafter immersed in 1.9 weight % of an aqueous sulfuric acid solution for 120 min at room temperature, and, after the chemical cleaning treatment, the chemically cleaning rubber sheet was prepared.

(6) An emulsion solution was prepared by mixing 25.0 g of an amino-modified dimethylsilicone oil bearing hydroxyl groups at both terminals (DOWSIL BY16-892: trade name, available from Dow-Toray Co., Ltd.), 2.7 g of a surfactant (NIKKOL BT-9: trade name, available from NIKKO Chemicals Co., Ltd.), and 72.3 g of 0.5 weight % of an aqueous acetic acid solution followed by stirring for 10 min at 8000 rotation/min with a homo-mixer.

(7) By using the above-prepared emulsion solution, the chemically cleaning rubber sheet was immersed in a mixture of aqueous solutions of an amino-modified dimethylsilicone oil with the final concentration of 0.05 weight % and sodium bicarbonate with the final concentration of 0.01 weight % at 40° C. for 45 min. Thereafter the rubber sheet was taken out of the liquid and, after immersion again in water, rinsed three times. The water-rinsing was performed every time by changing the water, and each time it was immersed for 1 min. And by treating by heat at 80° C. for 60 min followed by drying, the interfacial modification layer having amino-modified silicone compounds was formed to cover the chemically cleaning rubber sheet.

(8) On the above chemically cleaning rubber sheet with an interfacial modification layer was set 50×20 mm of a PET film, and a part of the sheet was masked. Then on this was put a square frame made of PMMA (outer diameter: 50×50 mm, inner diameter: 40×40 mm, height: 2 mm), and into this frame was flowed an addition-curing type silicone rubber (KE-1950-30A/B: trade name, available from Shin-Etsu Chemical Co., Ltd., Duro 30°). Then upon grading until the surface was smooth, the whole was heated to cure in a heating oven (DKM300: trade name, available from Yamato Scientific Co., Ltd.) at 140° C. for 1 h. After curing, removal of the frame, cutting off areas where the silicone was not in contact, positioning the masking at the top, and cutting in short with 20 mm wide gave the rubber sheet for adhesion strength evaluation.

(9) (Evaluation of Adhesion Strength)

(10) The evaluation of adhesion strength of the above-obtained rubber sheet for adhesion strength evaluation was performed by using an instrument of a digital force gauge (HF-100: trade name, available from Japan Instrumentation System Co., Ltd.) at a tension speed of 50 mm/min with a peeling angle 180°. The results are shown in Table 1.

Example 2

(11) In the same manner as Example 1, the chemically cleaning rubber sheet was prepared. To this sheet, after forming the interfacial modification layer, was applied a primer-blended agent, which was prepared by mixing a primer treatment agent A: primer C (trade name, available from Shin-Etsu Chemical Co., Ltd.), aluminum chelate D (trade name, available from Kawaken Fine Chemicals Co., Ltd.) and xylol (xylene WAKO special grade: trade name, available from FUJIFILM Wako Pure Chemical Corporation) in a weight ratio of 30:0.3:70 with a spray gun and dried at room temperature for 30 min to prepare the rubber sheet with a primer layer on the interfacial modification layer.

(12) In the same manner as Example 1, the rubber sheet for adhesion strength evaluation was prepared from the rubber sheet with a primer layer on the interfacial modification layer, and the evaluation was performed similarly. The results are shown in Table 1.

Example 3

(13) The primer treatment agent B: primer C (trade name, available from Shin-Etsu Chemical Co., Ltd.), Acrydic A-9585 (trade name, available from DIC Corporation), and xylol (xylene WAKO special grade: trade name, available from FUJIFILM Wako Pure Chemical Corporation) were mixed together in a weight ratio of 30:0.3:70 to afford a primer-blended agent. This agent was used to form the rubber sheet for adhesion strength evaluation similarly as shown in Example 2, and the evaluation was performed similarly. The results are shown in Table 1.

Example 4

(14) The primer treatment agent C: primer C (trade name, available from Shin-Etsu Chemical Co., Ltd.), DOWSIL RSN-0805 Resin (trade name, available from Dow-Toray Co., Ltd.) and xylol (xylene WAKO special grade: trade name, available from FUJIFILM Wako Pure Chemical Corporation) were mixed together in a weight ratio of 30:0.3:70 to afford the primer-blended agent. This agent was used to form the rubber sheet for adhesion strength evaluation similarly as shown in Example 2, and the evaluation was performed similarly. The results are shown in Table 1.

Comparative Example 1

(15) In the same manner as Example 1, the chemically cleaning rubber sheet was prepared, and without forming an interfacial modification layer, the rubber sheet for adhesion strength evaluation was prepared, and the evaluation was performed similarly. The results are shown in Table 1.

Comparative Example 2

(16) 25 g of the polyether-modified organosiloxane (KM-244F: trade name, available from Shin-Etsu Chemical Co., Ltd.), 2.7 g of a surfactant (NIKKOL BT-9: trade name, available from NIKKO Chemicals Co., Ltd.) and 72.3 g of 0.5 wt % of aqueous acetic acid solution were mixed to afford the emulsion solution. This solution was used to form the interfacial modification layer with a rubber sheet for adhesion strength evaluation similarly as shown in Example 1, and the evaluation was performed similarly. The results are shown in Table 1.

Comparative Example 3

(17) The emulsion solution of dimethylsilicone oil (KM-742T: trade name, available from Shin-Etsu Chemical Co., Ltd.) was used to form the interfacial modification layer with a rubber sheet for adhesion strength evaluation similarly as shown in Example 1, and the evaluation was performed similarly. The results are shown in Table 1.

(18) TABLE-US-00001 TABLE 1 Ex. Ex. Ex. Ex. Comp. Comp. Comp. 1 2 3 4 Ex. 1 Ex. 2 Ex. 3 Interfacial DOWSIL BY Yes Yes Yes Yes Modification 16-892 Layer (Amino-modified) KM-244F Yes (Polyether-modified KM-742T Yes (Dimethylsilicone) Primer Primer Treatment Yes Layer Agent A Primer Treatment Yes Agent B Primer Treatment Yes Agent C Adhesion n = 1 8.8 9.9 9.7 12.4 0.3 0.4 0.5 Strength n = 2 11.5 10.4 12.2 11.3 0.3 0.3 0.4 (N) n = 3 11. 10.2 12.0 10.9 0.3 0.1 0.5 Maximum 11.5 10.4 12.2 12.4 0.3 0.4 0.5 Average 10.4 10.2 11.3 11.5 0.3 0.2 0.4

(19) As Table 1 shows, in examples 1-4, the adhesion strength was strong and compared to comparative examples 1-3 excellent results were obtained.

(20) Next, the evaluation was performed as a gasket for medical use.

Example 5

(21) In the same manner as Example 1, the composition for rubber parts was prepared and cut properly in an automatic machine to fill into the cavity of the vulcanization mold with an appropriate weight and shape, and the rubber raw material was pre-molded. This pre-molded rubber raw material was put into the gasket-forming mold followed by press-heating in the vulcanization-molding press-machine at 180° C. for 10 min, and, after vulcanization and molding into the gasket-shape, a rubber part sheet for gaskets was obtained.

(22) A number of the gasket-shapes formed in the above sheet were vent-pressed, and then cut into an appropriate-shaped piece using a pulling mold to afford the rubber part for gaskets.

(23) The above rubber part for gaskets was immersed in 0.6 weight % of an aqueous sodium carbonate solution, after boiling for 90 min, and immersed again in 1.9 weight % of an aqueous sulfuric acid solution at room temperature for 120 min as a chemically cleaning treatment. Finally, the rubber part was taken out of the solution to afford the chemically cleaning gaskets

(24) An emulsion solution was prepared by mixing 25.0 g of an amino-modified dimethylsilicone oil bearing hydroxyl groups at both terminals (DOWSIL BY16-892: trade name, available from Dow-Toray Co., Ltd.), 2.7 g of a surfactant (NIKKOL BT-9: trade name, available from NIKKO Chemicals Co., Ltd.), and 72.3 g of 0.5 weight % of an aqueous acetic acid solution followed by stirring for 10 min at 8000 rotation/min with a homo-mixer.

(25) By using the above-prepared emulsion solution, the rubber part for chemically cleaning gaskets was immersed in a mixture of aqueous solutions of amino-modified dimethylsilicone oil with the final concentration of 0.05 weight % and sodium bicarbonate with the final concentration of 0.01 weight % at 40° C. for 45 min. Thereafter the rubber part was taken out of the liquid and, after immersion again in water, rinsed three times. The water-rinsing was performed every time by changing the water, and each time it was immersed for 1 min. By treating by heat at 80° C. for 60 min and drying the interfacial modification layer having amino-modified silicone compounds was formed to cover the rubber part.

(26) A silicone resin (X-40-2667A: trade name, available from Shin-Etsu Chemical Co., Ltd.) was heated to cure at 105° C. for 2 h followed by at 170° C. for 2 h in order to obtain a hardened material, and then it was crushed with a ball mill and classifying, to afford 20 weight % of silicone fine particles with an average diameter of 10 μm. A mixture of an addition-curing-type silicone rubber (KE-1950-30A/B: trade name, available from Shin-Etsu Chemical Co., Ltd., Duro A hardness 30°), 20 weight % of the silicone fine particles and xylol (xylene WAKO special grade: trade name, available from FUJIFILM Wako Pure Chemical Corporation) in a weight ratio of 8:2:90 was applied onto the rubber part for chemically cleaning gaskets that has the formed interfacial modification layer by a spray gun to form a coating film with 10 μm thickness, treated by heat at 140° C. for 60 min and cured. This gave a coating layer on the interfacial modification layer, and the desired slidable rubber material for medical use was obtained.

(27) (Evaluation of Sliding Resistance)

(28) The above slidable rubber material was attached to a plunger of a syringe barrel for 1 mL (inner diameter ca. φ6.35 mm) with a COP-resin outer barrel. To this syringe barrel, a plunger with a slidable rubber material was pushed 10 mm from a barrel flange, and then the syringe was installed in a fixture for measuring sliding resistance.

(29) After the syringe was installed in a fixture, an instrument of a digital force gauge (HF-100: trade name, available from Japan Instrumentation System Co., Ltd.) was placed at the bottom of the plunger followed by pushing in 30 mm at a push speed of 100 mm/min, and then the maximum load at that time was evaluated as a sliding resistance. Furthermore, when the plunger was sucked by hand after push-in, it was checked if the plunger could escape from the slidable rubber material: i.e., 0 indicates what was not missing, and X indicates what was missing. The results are shown in Table 2.

(30) (Evaluation of Leakage Resistance)

(31) According to JIS T3210, the leakage evaluation was performed. The slidable rubber material was attached to the syringe barrel for 1 mL (inner diameter ca. φ6.35 mm) with a COP-resin outer barrel and 0.75 mL of water was put in the syringe. Then, after fixing it to prevent water from coming out of the barrel, pressure was applied to the plunger at 490 kPa for 10 sec. In this case, after confirmation of no drops of water from the mating part, leakage was evaluated: i.e., 0 indicates that there was no leak, and X indicates that the leak occurred. The results are shown in Table 2.

(32) (Evaluation of Insoluble Particles)

(33) According to The Japan Pharmacopeia Seventeenth Edition, General Test 6.97, Insoluble Fine Particles Testing Method for Injector, 1st Method of Optical Shielding Particle Measurement, the evaluation of insoluble particles was performed. The slidable rubber material and the COP-resin outer barrel for 5 mL were both rinsed with water for fine particles testing. This slidable rubber material and plunger were attached to the outer barrel, after suction of 5 mL of water for fine particles testing, and then drained into a clean container. This operation was performed 10 sets. After combining these fluids followed by allowing to stand for 2 min to remove air bubbles, a testing fluid was in hand. Then in this testing fluid the number of particles with particle sizes of 10 μm or more and 25 μm or more was respectively measured by four fractions with a particle counter for liquid (KL-06: trade name, available from RION Co., Ltd.): conditions, dilution ratio=1, suction flow=25 mL and measurement amount=5 mL. After the first fraction was discarded, an average number of particles in the testing liquid was determined from the measurement of remained three fractions, and the number of fine particles per one rubber material was calculated. The results are shown in Table 2.

Example 6

(34) In the same manner as Example 5, the rubber parts for chemically cleaning gaskets that formed an interfacial modification layer were prepared and a mixture of an addition-curing-type silicone rubber (KE-1950-30A/B: trade name, available from Shin-Etsu Chemical Co., Ltd., Duro A hardness 30°), a silicone resin as solid fine particles (X-40-2667A: trade name, available from Shin-Etsu Chemical Co., Ltd.) was heated to cure at 105° C. for 2 h followed by at 170° C. for 2 h, after crushing with a ball mill, to afford the hardener product. A mixture of this product, 15 weight % of silicone particles with an average diameter of 2 μm obtained by classification and xylol (xylene WAKO special grade: trade name, available from FUJIFILM Wako Pure Chemical Corporation) in a weight ratio of 8.5:1.5:90 was applied to the above rubber parts by a spray gun to form the coating film with 10 μm thickness. The product was treated by heat at 140° C. for 60 min and cured to afford the slidable rubber materials. The evaluation results are shown in Table 2.

Example 7

(35) In the same manner as Example 5, the rubber parts for chemically cleaning gaskets that formed an interfacial modification layer were prepared and a mixture of addition-curing-type silicone rubber (KE-1950-30A/B: trade name, available from Shin-Etsu Chemical Co., Ltd., Duro A hardness 30°), 5 weight % of precipitated silica as solid fine particles (VN3 (average particle diameter 10 μm): trade name, available from Tosoh-Silica Co., Ltd.), and xylol (xylene WAKO special grade: trade name, available from FUJIFILM Wako Pure Chemical Corporation) in a weight ratio of 9.5:0.5:90 was applied to the above rubber parts by a spray gun to form the coating film with 10 μm thickness. The product was treated by heat at 140° C. for 60 min and cured to afford the slidable rubber materials. The evaluation results are shown in Table 2.

Comparative Example 4

(36) In the same manner as Example 5, the rubber parts for chemically cleaning gaskets that formed an interfacial modification layer were prepared and a mixture of addition-curing-type silicone rubber (KE-1950-30A/B: trade name, available from Shin-Etsu Chemical Co., Ltd., Duro A hardness 30°) and xylol (xylene WAKO special grade: trade name, available from FUJIFILM Wako Pure Chemical Corporation) in a weight ratio of 10:90 was applied to the above rubber parts by a spray gun to form coating films with 10 μm thickness. The product was treated by heat at 140° C. for 60 min and cured to afford the slidable rubber materials. The evaluation results are shown in Table 2.

(37) TABLE-US-00002 TABLE 2 Particle Comp. Material Size Ex. 5 Ex. 6 Ex. 7 Ex. 4 Solid Fine Silicone  2 μm Yes Particles Resin 10 μm Yes Silica 10 μm Yes Sliding n = 1 5.4 6.4 6.9 10.3 Resistance n = 2 5.2 6.5 7.0 11.0 (N) n = 3 5.6 6.3 6.8 10.1 Maximum 5.6 6.5 7.0 11.0 Average 5.4 6.4 6.9 10.5 Pulling out Evaluation O O O X during Suction Leakage n = 1 O O O O Resistance n = 2 O O O O n = 3 O O O O Evaluation Suitable Suitable Suitable Suitable Insoluble n = 1 10 μm 6 3 5 5 Particles 25 μm 0 0 0 0 n = 2 10 μm 3 1 8 7 25 μm 0 0 0 0 n = 3 10 μm 3 0 3 5 25 μm 0 0 0 0 Particle 10 μm 4 1 5 6 Average 25 μm 0 0 0 0 Evaluation Suitable Suitable Suitable Suitable

(38) As shown in Table 2, in examples 5-7, the slidable resistance was lower than the comparative example 4 and low slidable resistance could suppress the plunger pull during suction. Furthermore, it expressed excellent leak resistance, fewer insoluble particles and excellent physical properties.

INDUSTRIAL APPLICABILITY

(39) The slidable rubber material of the present invention can be used as follows: syringes that inject a liquid medicine into patients after inhaled it and then pushed it out, pre-filled syringes that inject a pre-sealed liquid medicine into patients by pushing it out when used or into an infusion solution, and syringes for blood drawing. In addition, this material can also be used as a variety of slidable rubber parts including medical gaskets, or the like.

(40) The method for producing the slidable rubber material elucidated in the present invention is simple to operate using inexpensive raw materials and easy to mass-produce with good yields. In conclusion, the method is useful for producing high quality slidable rubber materials.