JPH0539362A - Production of corrosion-resistant finger stall - Google Patents

Abstract

PURPOSE:To produce a corrosion-resistant finger stall which is flexible, age- resistant, solvent-resistant, water-resistant, and lowly sticky by molding a composite latex obtd. by three-dimensionally cross-linking a specific coreactive natural rubber latex. CONSTITUTION:40-10 pts.wt. methyl methacrylate is grafted onto 60-90 pts.wt (dry basis) natural rubber latex. The resulting graft copolymer is prevulcanized using a redox cross-linker consisting of an org. peroxide and a polyamine. 30-70 pts.wt. (dry basis) the resulting coreactive natural rubber latex and 70-30 pts.wt. (dry basis) reactive acrylic latex are mixed and then three-dimensionally cross-linked with a curative reactive with reactive side chains of the acrylic latex. The prepd. composite latex is molded by using it alone or by adhering it to the front surface or to the front and back surfaces of a sulfur- or thiuram- vulcanizing latex compsn., thus giving the objective stall.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention has no migration of sulfur content on the surface, and therefore has no possibility of adverse effects such as rusting and contamination when touching the metal surface of copper, silver or their compounds. It is about the sex finger cot. This finger cot is especially suitable for use in assembling high-performance electronic components, but it goes without saying that it can be used for general office work, medical care, etc. It can also be applied to structure sack, gloves, etc.

[0002]

2. Description of the Related Art In assembling high-performance electronic parts, natural rubber vulcanized rubber using sulfur or sulfur donors is generally used in order to prevent migration contamination of sweat and fat by bare hands. In this method, the free sulfur remaining in the rubber product migrates to the surface of the product, which causes rusting on the target metal surface, causing contamination, and also has the drawbacks of lowering the electrical conductivity of the electrical contacts.

On the other hand, the present inventors once invented a co-reacting natural rubber latex in which monomethyl methacrylate was graft-polymerized on a natural rubber latex and further prevulcanized with a redox crosslinking agent composed of an organic oxide and polyamine. Kokai 56-20180), the corrosion-resistant finger cot was industrialized. However, although it was possible to secure corrosion resistance to metal surfaces, improvements in product flexibility, aging resistance, and "powder-free" by preventing surface tackiness, as well as moisture absorption resistance and solvent resistance However, it is necessary to study to improve the alkali resistance.

[0004]

The present invention has been made in view of the above, and an object thereof is to prevent contact corrosiveness with respect to copper, silver and metal compounds thereof and to be suitable for precision work. The object is to create a corrosion-resistant finger sack having such finger sack properties, that is, flexibility, aging resistance, solvent resistance, moisture absorption resistance, alkali resistance and low tackiness.

[0005]

In order to achieve the above object, the means adopted by the present invention is to graft-polymerize monomethylmethacrylate on natural rubber latex, and then to latex obtained by carrying out an organic peroxide sulfur reaction, A specific reactive acrylic latex is added in a predetermined amount in the coexistence of a curing catalyst corresponding to the reactive side chain, and the obtained composite polymer latex is molded into a finger sack.

Here, the specific reactive acrylic latex is a latex in which methyl methacrylate or styrene is used as the hard component monomer and butyl acrylate or 2-ethylhexyl acrylate is used as the soft component monomer as the skeleton of the polymer. This backbone polymer is
In order to improve the compatibility with the natural rubber latex, long-chain ones are preferable.

On the other hand, as the reactive side chain, it is necessary to select two or more kinds from an amide group, a hydroxyl group, a carboxyl group and an epoxy group and carry out addition polymerization in combination. Also, the curing agent is
Thermosetting resin, such as alkylated methylol melamine,
Alternatively, it is selected from metal oxides such as zinc oxide.
This curing reaction is also performed in the drying step during molding.

[0008]

The polymer morphology of the anticorrosive finger cot obtained by the present invention is one in which methyl methacrylate / grafted vulcanized natural rubber and crosslinked acrylic resin constitute a uniform matrix, whereby aging resistance etc. Is thought to improve. The skeleton polymer of the reactive acrylic latex needs to have 10 to 20 chain carbon atoms, and particularly preferably 12 to 15 carbon atoms for compatibility. The reactive acrylic latex is one in which two or more kinds of reactive side chains are combined and introduced into a polymer, and has a vitrification transition point (Tg) of -70 to.
If one having a temperature of + 50 ° C. is selected, a three-dimensional mesh can be easily formed.

As shown in FIG. 1, a finger sack is molded from only the composite latex 1, or, as shown in FIG.
The composite latex 1 may be attached to the surface of a conventional sulfur-vulcanized compounded latex 2 or thiuram sulfur compounded latex to form a finger sack. Further, as shown in FIG. 3, the composite latex 1 may be attached to both the front surface and the back surface of the conventional latex 2 to form a finger sack.

When the polymer skeleton of the reactive acrylic latex is composed of a hard component monomer, the molded finger sack has a reduced elongation depending on the addition amount as compared with that composed of only natural rubber latex, and when it is composed of a soft component monomer, Since the elongation increases according to the added amount, it is possible to impart a desired elongation to the finger sack.

[0011]

EXAMPLES The present invention will be described based on examples and comparative example finger cots. Sample 1 (Example: Composite latex finger cot) First step: 75 parts by weight of natural rubber latex and 25 parts by weight of monomethyl methacrylate were graft-polymerized, and then a redox crosslinking agent was added to prevulcanize. Second step: Co-reacted natural rubber latex obtained in the first step 50 Reactive acrylic latex 50 composed of 50 parts by weight of a soft component monomer (butyl acrylate)
Dry parts by weight were added, and zinc oxide was made to act on this as a curing agent to form a composite latex. Third step: forming a finger cot. Sample 2 (Composite Example: Latex Finger Sack) 1st step: same as sample 1, 2nd step: Co-reacted natural rubber latex obtained in 1st step 50 parts by weight of hard component monomer (methyl methacrylate) Reactive acrylic latex 5
0 dry weight part was added, and an alkylated methylol melamine resin was made to act on this as a hardening | curing agent, and it was set as the composite latex. 3rd step: same as sample 1, sample 3 (comparative example: natural rubber single latex finger sack) 1st step: same as sample 1, 2nd step: none, 3rd step: same as sample 1, sample 4 (comparison Example: Soft acrylic simple latex latex finger sack) First step: None, Second step: A reactive acrylic latex composed of a soft component monomer (butyl acrylate) was reacted with zinc oxide as a curing agent. 3rd step: same as sample 1, sample 5 (comparative example: soft acrylic simple latex finger cot) 1st step: none, 2nd step: hard component monomer (methyl methacrylate)
An alkylated methylolmelamine resin was made to act as a curing agent on the reactive acrylic latex composed of. Third step: same as sample 1, about finger sack films of materials 1 to 5 before and after standing in hot air at 100 ° C. for 48 hours, that is, physical properties before and after aging, M500 (Kgf / cm) ² : indicates stress and bending resistance when the film is stretched 6 times), T
B (Kgf / cm ^2: stress when cut by pulling the film, indicating the intensity), EB (%: extending rate when taken stretched films, exhibitions showing the elongation property) was measured. or,
Surface tackiness of each sample (touch feeling judgment, A: extremely small,
B: Yes, C: Extremely large, Water resistance (Visual judgment,
A: No whitening, B: Whitening, C: Whitening, Alkali resistance (strength after immersion in 20% KOH solution, A: No change,
B: A decrease in strength is recognized) and solvent resistance (visual judgment after immersion in benzene, A: little swelling, C: large swelling) were evaluated. The measurement and evaluation results are shown in Table 1 Film characteristics.

[0012]

[Table 1]

From this table, the finger cots made of the composite latexes of the examples of Samples 1 and 2 have improved aging resistance and good surface tackiness, water resistance, alkali resistance and solvent resistance. It can be seen that it is. Further, from this table, the finger sack made of the comparative example natural rubber simple substance latex of Sample 3 is inferior in aging resistance, and the finger sack made of the comparative example soft acrylic simple substance latex of Sample 4 is good in aging resistance, It is understood that the finger sack made of the comparative sample hard acrylic simple substance latex of Sample 5 which is inferior in surface tackiness and solvent resistance is good except for the extensibility, but the extensibility is poor and too hard.

[0014]

As described above, the film of the anticorrosive finger sack molded by the method of the present invention is a film obtained by the sulfur vulcanization method of natural rubber latex, a film made by the thiuram vulcanization method, or an acrylic latex. Compared with a film prepared by mere vulcanization, or a film obtained by vulcanizing methyl methacrylate / grafted natural rubber latex with a chemical oxide, flexibility (expandability), aging resistance, solvent resistance, water resistant,
Improvements are observed in many respects such as tackiness.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a single layer finger sack produced by the method of the present invention, the finger sack consisting only of composite latex.

FIG. 2 is a cross-sectional view of a multi-layered finger sack manufactured by the method of the present invention, in which the surface layer is a composite latex and the back layer is a natural rubber latex.

FIG. 3 is a cross-sectional view of a three-layer finger sack manufactured by the method of the present invention. In this finger sack, the surface layer and the back layer are composite latex, and the intermediate layer is natural rubber latex.

[Explanation of symbols]

 1: Composite latex 2: Natural rubber latex

Claims (2)

[Claims] 1. A natural rubber latex of 60 to 90 dry parts by weight and a monomethyl methacrylate of 40 to 10 parts by weight are graft-polymerized, and then a redox crosslinking agent composed of an organic peroxide and a polyamine is added, which is pre-added. 70 to 30 dry parts by weight of reactive acrylic latex is added to 30 to 70 dry parts by weight of the co-reacted natural rubber latex obtained by the first step of vulcanization and the thermosetting resin or metal. A second step in which a curing agent corresponding to the reactive side chain of the acrylic latex such as an oxide is allowed to act to form a three-dimensional reticulation, and the composite latex obtained in the second step is used as a simple substance or as a sulfur It comprises a third step in which the vulcanized compounded latex or thiuram vulcanized compounded latex is attached to the front surface or the front and back surfaces and molded into a predetermined shape. Corrosion protection finger sack production method with butterflies. 2. A reactive acrylic latex is a long-chain acrylic ester in which two or more reactive side chains are combined and introduced into a polymer, and has a vitrification transition point (Tg) of −.
The method for producing an anticorrosive finger cot according to claim 1, wherein the polymer latex is in the range of 70 to + 50 ° C.