JP2003336113A - Soft nitrile medical glove without containing zinc oxide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substitute for natural rubber latex gloves for a some kind of person, since it was found out that the protein of the natural rubber latex itself cause an allergic reaction in such the person, although this is a very rare case. <P>SOLUTION: This new composition for producing nitrile gloves is developed. The obtained gloves have following marked characteristics. Strain at 6 min is ≥50% of its initial value, an extreme tensile strength and elongation are sufficiently higher than standard values required in accordance with the ASTM, and the gloves have very lower modulus values than those of the almost all of commercial nitrile gloves. The peculiar composition does not contain zinc oxide and vulcanized at 149-204°C (300-400°F) temperature range for 5-60 min. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

The present application seeks priority of priority provisional patent application Serial No. 60 / 29,320 dated 2001.5.22.

[0002]

BACKGROUND OF THE INVENTION Natural rubber latex gloves are
It has excellent protection from many dangerous toxic substances and many unpleasant chemicals. The natural rubber latex glove manufacturing industry grew rapidly in the early 1980s, especially in the Far East. However, shortly thereafter, the protein of the natural rubber latex itself was found to cause an allergic reaction (type I) in some people. In rare cases, an alternative to natural rubber latex gloves must be provided for these people.

[0003]

[Description of Related Technology] Nitrile Butadiene Rubber (NB
R), polychloroprene (CR), polyurethane (P
U), polyisoprene (PI), polyvinyl chloride (vinyl, PVC), polyethylene (PE), etc. and a series of synthetic materials including many mixtures and copolymers thereof have been used in place of natural rubber latex,
Not all the performance and costs of that alternative were satisfactory. Among these alternatives, nitrile butadiene rubber is one of the best and is an elastic glove at a reasonable cost.

US Pat. No. 5,014,3 to Tillotson et al.
62 and Reissue Patent RE 35,616 describe nitrile butadiene rubber gloves. This patent describes relaxation properties. The stress (ie modulus) of a material under a constant force of 6 minutes should be less than 50% of its initial value. Most of the nitrile gloves currently on the market have a group of relaxation properties around 40%, which varies from 30 to 50%. Other gloves have improved tensile strength or elongation or Type I
It has a small amount of additives (ZnO etc.) that cause the V allergic reaction. None of these exhibit a 6 minute relaxivity above 50%.

Relaxation properties are not an ASTM defined quality control parameter for gloves. However, along with modulus, along with other non-ASTM quality control parameters for gloves, they characterize the performance and tactile sensation of the glove. The higher the relaxation properties, the better the glove will conform to the shape of the hand. On the other hand, gloves become loose after a while. However, in combination with a high degree of relaxation and high modulus, gloves will quickly tire your fingers. Natural rubber latex gloves
Relaxation of 80% or more, 300% modulus of 2MPA
Below, nitrile butadiene rubber gloves have a very high 300% modulus (7 MPa or less) with low relaxivity (typically 40%).

Relaxation properties are an inherent property of natural materials.
Most of the nitrile butadiene latices produced via emulsion polymerization provided a relaxivity of about 40%, which was proven by the currently available nitrile gloves. This unique property is preferentially caused by the polymer chain structure and is determined by the polymerization mechanism. Different nitrile butadiene rubber commercial products have different control parameters and processing methods, but they all differ little due to the use of emulsion polymerization for economic reasons.

Polymerization mechanism other than emulsion polymerization, that is,
Nitrile butadiene latex produced by dip polymerization has a completely different structure and therefore a different relaxation profile, but due to cost, there is currently no such product on the market. If the polymer chain structure is expected during the polymerization, it cannot be manipulated. It is an object of the present invention to adjust this parameter (relaxation) to 50% or more. Therefore, other mechanical properties are AS
Must meet TM requirements.

[0008]

SUMMARY OF THE INVENTION The present invention resides in a unique combination of zinc oxide-free composition and selected vulcanization conditions, which comprises:
It can be economically achieved by a normal manufacturing facility.
The gloves produced have a relaxation property at 50% or more and a low modulus (about 3 Mpa). Gloves are
Substantial ultimate tensile strength (> 20Mpa) and elongation (> 50)
0%) is retained. Gloves for 5-60 minutes, 149-2
Manufactured by vulcanization treatment maintained in the temperature range of 04 ° C (300-400 ° F). Tensile strength and elongation are better than ASTM standards for medical gloves. The current ASTM standard is ASTM D412-92.
With sufficient vulcanization, the thin films produced exhibit satisfactory protection against virus penetration. The tear strength is also good due to the low modulus.

[0009]

Detailed Description of the Preferred Embodiments Composition : Carboxylated nitrile butadiene rubber is a normal composition and in vulcanization,
Two types of cross-linking are performed. The first is where the carboxylic acid groups are each linked to the other via a reaction with zinc oxide at room temperature. The second type of cross-linking is that in which the unsaturated butadiene block bonds at elevated temperatures via a conventional sulfur system.

With zinc oxide, the relaxation properties are not very sensitive to changes in zinc oxide content, while other mechanical properties (modulus, ultimate elongation, and tensile strength) are preferred. One of the inventor's preferred compositions can be compared with that of natural rubber latex (300% modulus <2 Mpa, tensile strength> 20 Mpa and at the same time elongation> 500%). However, the relaxation characteristic for 6 minutes is not more than 45%. Therefore, zinc oxide was removed to prevent performance degradation. The compositions obtained are shown in the table below.

[0011]

[Table 1]

Vulcanization Conditions: Zinc oxide has been used as a primary activator in conventional vulcanization systems. Higher temperatures were used during vulcanization by removing zinc oxide. After leaching, the film was dried at 127 ° C (260 ° F) and then 149-204 ° C (300-40 ° C).
It was vulcanized at 0 ° F) for 5-60 minutes. Typically, the cure temperature is 116-140 ° C (240 ° F-285 ° F).

Mechanical Properties: A pair of thin films obtained with the above composition and vulcanization conditions exhibit the following properties.

[Table 2]

As a result, the inventors have discovered a zinc-free composition and vulcanization conditions which result in higher relaxation properties and which results in improved soft gloves. This combination provides a more balanced performance (performance).

Compounds without zinc show relaxation properties near 55%. Powdering and / or extraction do not have a significant impact on glove properties. The composition produces improved compounds and optimizes vulcanization conditions (temperature and processing time),
The novel composition and processing method are easily realized economically under the conventional nitrile-glove manufacturing line. Depending on the desired application, both powdered and powderless gloves can be manufactured with the same composition.

Although the present invention has been described in terms of preferred embodiments, modifications and alternatives will be apparent to those skilled in the art without departing from the spirit of the invention.

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08K 5/13 C08K 5/13 5/39 5/39 5/47 5/47 C08L 9/04 C08L 9/04 F term (Reference) 3B033 AB01 AB06 AB08 AC03 4F071 AA12X AA34X AA76 AB04 AB18 AC11 AC13 AE02 AE03 AF15 AF20 AH19 BA05 BC07 BC17 4J002 AC071 DA046 DE059 DE139 EJ038 EV137 EV349 FD146 FD157 FD158 FD159 GB01 HA07

Claims (27)

[Claims] 1. Nitrile butadiene rubber latex; sulfur; zinc dibutyldithiocarbamate; 2,2 '
-Zinc oxide-free elastomeric composition for gloves, characterized in that it has methylene-bis- (4-methyl-6-butylphenol); and zinc 2-mecaptobenzothiazole. 2. The zinc oxide-free elastomeric composition of claim 1, wherein sulfur is present in an amount of about 3.0 parts by weight per 100 parts by weight of nitrile butadiene rubber. 3. The zinc oxide-free elastomeric composition of claim 1, wherein the titanium dioxide is present in an amount of about 0.5 parts by weight per 100 parts by weight of nitrile butadiene rubber. 4. Zinc dibutyldithiocarbamate,
About 1.0 per 100 parts by weight of nitrile butadiene rubber
The zinc oxide-free elastomeric composition according to claim 1, characterized in that it is present in an amount of parts by weight. 5. The zinc oxide-free elastomer composition of claim 1, wherein potassium hydroxide is present in an amount of about 1.0 part by weight per 100 parts by weight of nitrile butadiene rubber. 6. The zinc oxide-free elastomeric composition of claim 1, wherein the zinc 2-mercaptobenzothiazole is present in an amount of about 1.0 part by weight per 100 parts by weight of nitrile butadiene rubber. . 7. The 2,2'-methylene-bis- (4-methyl-6-butylphenol) is present in an amount of about 0.5 parts by weight per 100 parts by weight of nitrile butadiene rubber. 2. The zinc oxide-free elastomer composition according to 1. 8. The glove is 149 to 204 ° C. (300 to
Elastomer composition without zinc oxide according to claim 1, characterized in that it is vulcanized in the temperature range of 400 ° F. 9. The zinc oxide-free elastomer composition of claim 1, wherein the glove is vulcanized in 5-60 minutes. 10. The glove is 149 to 204 ° C. (300
The zinc oxide-free elastomeric composition according to claim 1, characterized in that it is vulcanized in the temperature range from 400 to 400 ° F. for 5 to 60 minutes. 11. A nitrile butadiene rubber latex of 100 parts by weight; 1.0 part by weight of zinc dibutyldithiocarbamate; 3.0 parts by weight of sulfur; 1.0 part by weight of 2,
2'-methylene-bis- (4-methyl-6-butylphenol); 1.0 part by weight potassium hydroxide; and 1.0
Zinc oxide-free elastomeric composition for gloves, characterized in that it has parts by weight of zinc 2-mecaptobenzothiazole. 12. The gloves are 149 to 204 ° C. (300
Elastomer composition without zinc oxide according to claim 11, characterized in that it is vulcanized in the temperature range from 400 to 400 ° F. 13. The zinc oxide-free elastomer composition of claim 11, wherein the glove is vulcanized in 5-60 minutes. 14. The glove is 149 to 204 ° C. (300
Elastomer composition without zinc oxide according to claim 11, characterized in that it is vulcanized in the temperature range from 400 to 400 ° F for 5 to 60 minutes. 15. A glove that has relaxation properties of 50% or more and is produced by a vulcanization process that is heated to a temperature range of 149 to 204 ° C. (300 to 400 ° F.) for 5 to 60 minutes. Zinc oxide-free nitrile butadiene rubber for gloves, characterized by: 16. The zinc oxide-free nitrile butadiene rubber for gloves according to claim 15, characterized in that the composition further contains sulfur. 17. Zinc oxide-free nitrile butadiene rubber for gloves according to claim 16, characterized in that sulfur is present in an amount of about 3.0 parts by weight per 100 parts by weight of nitrile butadiene rubber. . 18. Zinc oxide-free nitrile butadiene rubber for gloves according to claim 16, characterized in that the composition further comprises zinc dibutyldithiocarbamate. 19. The zinc dibutyldithiocarbamate is present in an amount of about 1.0 part by weight per 100 parts by weight nitrile butadiene rubber.
Zinc oxide-free nitrile butadiene rubber for gloves, as described in 1. 20. Zinc oxide-free nitrile butadiene rubber for gloves according to claim 15, characterized in that the composition further comprises titanium dioxide. 21. The zinc oxide-free nitrile for gloves according to claim 20, wherein the titanium dioxide is present in an amount of about 0.5 parts by weight per 100 parts by weight of the nitrile-butadiene rubber. Butadiene rubber. 22. The composition of claim 1, further comprising zinc 2-mercaptobenzothiazole.
5. Zinc oxide-free nitrile butadiene rubber for gloves according to item 5. 23. The zinc 2-mercaptobenzothiazole is present in an amount of about 1.0 part by weight per 100 parts by weight of nitrile butadiene rubber.
Zinc oxide-free nitrile butadiene rubber for gloves, as described in 1. 24. The glove according to claim 15, wherein the composition further comprises 2,2′-methylene-bis- (4-methyl-6-butylphenol).
Nitrile butadiene rubber without zinc oxide. 25. 2,2′-methylene-bis- (4-
Methyl-6-butylphenol) is present in an amount of about 0.5 parts by weight per 100 parts by weight of nitrile butadiene rubber, glove-free, zinc oxide-free nitrile butadiene rubber. . 26. Zinc oxide-free nitrile butadiene rubber for gloves according to claim 15, characterized in that the composition further comprises potassium hydroxide. 27. The glove according to claim 26, wherein potassium hydroxide is present in an amount of about 1.0 part by weight per 100 parts by weight of nitrile butadiene rubber.
Nitrile butadiene rubber without zinc oxide.