Search

KR-102961912-B1 - LATEX COMPOSITION FOR DIP-FORMING WITH EXCELLENT DISPERSION STORAGE STABILITY, METHOD FOR PREPARING THEREOF, AND A DIP-FORMED ARTICLE PREPARED THEREFROM

KR102961912B1KR 102961912 B1KR102961912 B1KR 102961912B1KR-102961912-B1

Abstract

A dip-molding latex composition comprising a carboxylic acid-modified nitrile copolymer latex, amorphous nanocellulose, and an anionic dispersant, having a dispersion stability (TSI) value of 2.5 or less for 48 hours, a method for manufacturing the same, and a dip-molded article obtained by dip-molding the dip-molding latex composition are provided.

Inventors

  • 김동환
  • 정성훈
  • 이하정

Assignees

  • 금호석유화학 주식회사

Dates

Publication Date
20260512
Application Date
20231023

Claims (20)

  1. A dip-molding latex composition comprising a carboxylic acid-modified nitrile copolymer latex, amorphous nanocellulose, and an anionic dispersant, having a dispersion stability (TSI) value of 2.5 or less for 48 hours.
  2. In paragraph 1, The above carboxylic acid-modified nitrile copolymer is, Based on the total weight of the above carboxylic acid-modified nitrile copolymer, 45~80 wt% of conjugated diene monomer; 15 to 45 wt% of ethylenically unsaturated nitrile monomer; and A latex composition for dip molding comprising 1 to 10 weight% of an ethylenically unsaturated acid monomer.
  3. In paragraph 2, A latex composition for dip molding, wherein the above-mentioned conjugated diene monomer is one or more selected from the group consisting of 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-pentadiene, and isoprene.
  4. In paragraph 2, A latex composition for dip molding, wherein the above-mentioned ethylenically unsaturated nitrile monomer is one or more selected from the group consisting of acrylonitrile, methacrylonitrile, fumaronitrile, α-chloronitrile, and α-cyanoethyl acrylonitrile.
  5. In paragraph 2, A latex composition for dip molding, wherein the above-mentioned ethylenically unsaturated acid monomer is one or more selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, maleic anhydride, citraconic acid anhydride, styrene sulfonic acid, monobutyl fumarate, monobutyl maleate, and mono-2-hydroxypropyl maleate.
  6. In paragraph 1, A latex composition for dip molding, wherein the content of the amorphous nanocellulose is 0.05 to 0.9 parts by weight per 100 parts by weight of the carboxylic acid-modified nitrile copolymer.
  7. In paragraph 1, The above amorphous nanocellulose is a latex composition for dip molding having an average diameter of 5 to 20 nm.
  8. In paragraph 1, The above amorphous nanocellulose is a latex composition for dip molding having a length of 5 to 100 μm.
  9. In paragraph 1, The above amorphous nanocellulose is TEMPO-oxidized nanocellulose, and the TEMPO oxidation degree is 1.0 to 2.0 mmol/g, a latex composition for dip molding.
  10. In paragraph 1, A latex composition for dip molding, wherein the above-mentioned anionic dispersant is one or more selected from the group consisting of sodium laureth sulfate, ammonium laureth sulfate, sodium laureth sulfonate, sodium lauryl sulfate, and ammonium lauryl sulfate.
  11. In paragraph 1, A latex composition for dip molding, wherein the content of the anionic dispersant is 0.1 to 0.5 parts by weight per 100 parts by weight of the carboxylic acid-modified nitrile copolymer.
  12. In paragraph 1, A latex composition for dip molding further comprising epoxy-modified isosorbide.
  13. In Paragraph 12, A latex composition for dip molding, wherein the content of the epoxy-modified isosorbide is 0.1 to 0.9 parts by weight per 100 parts by weight of the carboxylic acid-modified nitrile copolymer.
  14. In paragraph 1, A latex composition for dip molding, further comprising one or more selected from the group consisting of pigments, vulcanizing agents, vulcanization accelerators, and crosslinking agents.
  15. In paragraph 1, A latex composition for dip molding, further comprising one or more selected from the group consisting of emulsifiers, polymerization initiators, molecular weight regulators, polymerization inhibitors, pH regulators, antioxidants, and oxygen capture agents.
  16. (a) a step of obtaining a carboxylic acid-modified nitrile copolymer latex by emulsion polymerization of a mixture of a conjugated diene monomer, an ethylenically unsaturated nitrile monomer, and an ethylenically unsaturated acid monomer; (b) a step of adding an amorphous nanocellulose solution to the carboxylic acid-modified nitrile-based copolymer latex and stirring to obtain a latex-nanocellulose masterbatch solution having a dispersion stability (TSI) value of 0.5 to 2.0 for 48 hours; and (c) a step of mixing the carboxylic acid-modified nitrile-based copolymer latex obtained in step (a) above with the latex-nanocellulose masterbatch solution obtained in step (b) above; A method for manufacturing a latex composition for dip molding, comprising
  17. delete
  18. In Paragraph 16, A method for preparing a latex composition for dip molding, wherein the latex-nanocellulose masterbatch solution comprises 50 to 300 parts by weight of the carboxylic acid-modified nitrile copolymer per 100 parts by weight of the nanocellulose.
  19. In Paragraph 16, A method for preparing a latex composition for dip molding, wherein in step (b) above, the amorphous nanocellulose solution comprises 0.1 to 0.9 weight percent of amorphous nanocellulose.
  20. In Paragraph 16, A method for manufacturing a latex composition for dip molding, wherein the stirring speed during stirring in step (b) above is 200 to 2,000 rpm.

Description

Latex composition for dip-forming with excellent dispersion storage stability, method for preparing therefrom, and a dip-formed article prepared therefrom The present specification relates to a latex composition for dip molding comprising a bio-derived material, a method for manufacturing the same, and a dip-molded article manufactured therefrom. Conventionally, the main raw material for gloves used for medical, agricultural and livestock processing, and industrial purposes was natural rubber latex. However, when using gloves made from natural rubber latex, the problem of users suffering from contact allergic diseases due to proteins contained in the natural rubber latex occurred frequently. Consequently, continuous attempts have been made to manufacture glove raw materials capable of replacing natural rubber latex. This has led to the production of gloves using protein-free synthetic rubber latex, such as carboxylic acid-modified nitrile copolymer latex. Since carboxylic acid-modified nitrile copolymer latex gloves possess higher puncture strength compared to conventional natural rubber latex gloves, demand is on the rise in the medical and food sectors, where contact with sharp objects is frequent. In particular, as medical gloves are used as disposable consumables, users tend to prefer thinner and tougher products. Along with this, there is a growing need to develop synthetic rubber latex products that require not only comfort but also biocompatibility in environments involving skin contact. However, clear limitations still exist in terms of biocompatibility, as allergic reactions to skin contact with synthetic rubber latex persist, and odors are present due to the cross-linking chemicals used. Meanwhile, methods to add biomass-derived natural polymers to synthetic rubber latex to impart biocompatibility are currently being explored. A representative natural polymer is nanocellulose, which has the advantage of being able to be manufactured from abundant resources on Earth. Non-patent document 1 mentions the improvement of physical properties through the formation of XNBR and zinc carboxylate networks (Zn 2+ carboxylate networks) within a closed system, rather than a solution crosslinking system such as a dipping process, using crystalline nanocellulose. Additionally, patent document 1 mentions the improvement of crosslinking properties of latex through the use of oxidized nanocellulose. However, these documents do not provide a solution for the changes in dispersion stability of nanocellulose over time. As such, if the dispersion stability of nanocellulose is not maintained, phase separation may occur after a certain period of time. Consequently, non-uniformity in compatibility between nanocellulose particles and rubber latex particles occurs during the dipping process, resulting in a non-uniform rubber molded body. Furthermore, changes in crosslinking density after crosslinking lead to a degradation of physical properties, causing problems such as poor product quality. Hereinafter, one aspect of the present specification will be described with reference to the attached drawings. However, the details described in the present specification may be implemented in various different forms and are therefore not limited to the embodiments described herein. Throughout the specification, when a part is described as "including" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but rather allows for the inclusion of additional components. When a range of numerical values is described in this specification, unless a specific range is otherwise described, the value has the precision of significant figures provided according to the standard rules in chemistry for significant figures. For example, 10 includes a range of 5.0 to 14.9, and the number 10.0 includes a range of 9.50 to 10.49. Latex composition for dip molding A latex composition for dip molding according to one aspect of the present specification comprises a carboxylic acid-modified nitrile copolymer latex, amorphous nanocellulose, and an anionic dispersant, and has a Turbiscan Stability Index (TSI) value of 2.5 or less for 48 hours. TSI is a dispersion stability evaluation index that compares changes in dispersion stability by quantifying the intensity and amount of light scattered from numerous particles when light is irradiated onto a solution contained in a container for a certain period of time. Specifically, the TSI value is calculated by a Turbiscan optical analysis method. When a laser is irradiated onto a solution containing particles, the laser causes scattering between multiple particles, and the intensity of this scattered light (backscattering light) is measured. If the concentration of the solution is dilute, the intensity of the transmitted light (forward scattering) changes over time. Since this is determined by the concentration of the solution and the size of the particles, it i