摘要:
A method of preparing a low allergic natural rubber latex which is less likely to cause allergy, comprising adding a protease having an exopeptidase activity to a natural rubber latex and aging the natural rubber latex, thereby to decompose a protein in the latex to such a degree that the protein and a protein decomposition product, which have a number-average molecular weight of 4500 or more, are not detected; a method of preparing a deproteinized natural rubber latex which is less likely to cause allergy, comprising adding an alkali protease to a natural rubber latex, thereby to decompose a protein in the latex, adding a protease having an exopeptidase activity, thereby to further decompose the protein and a decomposition product thereof in the latex, and removing the protein and the decomposition product thereof; a low allergic natural rubber obtained by a decomposition treatment of a protein, wherein the protein and a protein decomposition product, which have a number-average molecular weight of 4500 or more, are not detected; and a deproteinized natural rubber obtained by a decomposition treatment and a removing treatment of a protein, wherein the content of the protein is 0.02% or less in terms of a nitrogen content, an absorption at 3280 cm−1 is not recognized in an infrared absorption spectrum, and the protein and a protein decomposition product, which have a number-average molecular weight of 4500 or more, are not detected.
摘要:
A modified natural rubber is disclosed, which is obtained by modifying a deproteinized natural rubber having a nitrogen content of less than 0.10% by weight. A process for improving the graft ratio and the graft efficiency of natural rubber and a process for improving the epoxidation ratio of natural rubber are also disclosed. The modified natural rubber of the present invention has a high modifying efficiency and thus shows an excellent modifying effect. It is also useful as a means for preventing allergy.
摘要:
Disclosed are a cationic deproteinized natural rubber latex, in which rubber particles are positively charged and the concentration of said rubber particles is from 40 to 65% by weight and that the viscosity at 25° C. of said latex is 200 mPa·s or less, a method of preparing said latex which comprises subjecting to a deprotenization treatment using a proteolytic enzyme and a deproteinizing agent made of one or more surfactant selected from cationic and nonionic surfactants, and optionally adding a post additive comprising a cationic or nonionic surfactant as an active component, thereby to enable both surfactants described above to coexist, and a treating agent used in the same.
摘要:
Disclosed are a deproteinizing agent comprising a proteolytic enzyme and one or more cationic surfactants selected from the group consisting of an alkylamine salt, an alkylamine derivative and quaternized compounds thereof; and a method of preparing a cationic deproteinized natural rubber latex, which comprises adding said deproteinizing agent to a field latex or an ammonia-treated latex thereby subjecting the latex to a deproteinization treatment and purifying the rubber particles in the latex.
摘要:
A means for stabilizing a deproteinized natural rubber latex is disclosed, comprising adding a stabilizer selected from the group consisting of (a) an anionic surfactant, (b) an amphoteric surfactant, (c) a nonionic surfactant, (d) a nonionic or amphoteric oligomer or polymer, and (e) an anionic oligomer or polymer. By adding the stabilizer, the mechanical stability of a deproteinized natural rubber latex can be markedly improved.
摘要:
A process for producing raw rubber from a deproteinized natural rubber is disclosed, which comprises coagulating rubber particles in the deproteinized natural rubber latex by: (1) adding a nonionic surfactant having a cloud point of from 20.degree. to 100.degree. C. and a molecular weight of 300 or more to the deproteinized natural rubber latex and heating the latex to a temperature not lower than the cloud point of the nonionic surfactant; or (2) adding a coagulation assistant selected from the group consisting of: (a) an anionic surfactant, (b) an amphoteric surfactant, (c) a nonionic surfactant, (d) a nonionic or amphoteric oligomer or polymer, and (e) an anionic oligomer or polymer, to the deproteinized natural rubber latex; and then recovering the coagulated rubber particles. According to the process of the present invention, raw rubber containing substantially no metal ion can be produced with a high efficiency.
摘要:
A method of producing a particulate natural rubber, which comprises adding an inorganic salt to a serum obtained by centrifugal separation of a natural rubber latex in the amount enough to cause separation of a particulate natural rubber component in the serum, thereby to isolate the particulate natural rubber component as a cream component.
摘要:
A steering column cover body accommodates therein at least one of an electric junction block, a meter and at least one switch which are directly connected with each other. The switch includes at least one of a turn switch, a wiper switch, a hazard switch and an ignition switch. The meter includes a circuit board on which a first circuit for driving the meter and a second circuit for driving the at least one switch is mounted.
摘要:
A route information inputting section inputs route information including route drawing information on routes of a plurality of wiring harnesses to be arranged within a vehicle and route length information of each wiring harness. A wiring information memory stores wiring information including auxiliary unit information on a plurality of auxiliary units connected to the plurality of wiring harnesses and wire information on attributes of a plurality of wires connected between the plurality of auxiliary units. A display section displays on a screen a route drawing based on the route information input. An auxiliary unit position assigning section assigns positions of the plurality of auxiliary units on the route drawing displayed on the screen based on the auxiliary unit information included in the wiring information stored by the wiring information memory. A route/wiring linking section mutually wire-connects the plurality of auxiliary units of which positions have been assigned by the auxiliary unit position assigning section through a selective route on the route drawing, and links the wiring information on the plurality of wire-connected auxiliary units to the route information on the selected route.
摘要:
There are provided a deproteinized natural rubber latex which comprises a purified product of proteolytically treated natural rubber latex and contains fine particles of natural rubber latex, a deproteinized natural rubber which comprises a dehydrated product of the deproteinized natural rubber latex, and a process for the production of deproteinized natural rubber latex which comprises subjecting a latex solution prepared by (1) adding water and/or a surfactant to a natural rubber latex and then proteolytically treating the resulting latex solution or (2) proteolytically treating a natural rubber latex and then adding water and/or a surfactant to the treated natural rubber latex, to purification using a rotary plate membrane separation apparatus. The deproteinized natural rubber latex contains substantially no protein, is excellent in film-forming property, and provides a raw rubber film having excellent green strength, and the process can produce the deproteinized natural rubber latex in a high yield with high production efficiency.