Dip-formed article comprising a layer derived from latex composition for dip-forming

1 . A dip-formed article comprising a layer derived from a latex composition for dip-forming,

the latex composition for dip-forming comprising:

an epoxy crosslinking agent, and

a carboxylic acid-modified nitrile-based copolymer latex, the carboxylic acid-modified nitrile-based copolymer latex comprising a carboxylic acid-modified nitrile-based copolymer, the carboxylic acid-modified nitrile-based copolymer comprising, based on a dry weight of the carboxylic acid-modified nitrile-based copolymer:

18 to 28 wt % of an ethylenically unsaturated nitrile-based monomer-derived unit,

67.5 to 79.5 wt % of a conjugated diene-based monomer-derived unit, and

2.5 to 4.5 wt % of an ethylenically unsaturated acid monomer-derived unit,

wherein an amount of the epoxy crosslinking agent added is 0.1 to 1.6 parts by weight based on 100 parts by weight of the carboxylic acid-modified nitrile-based copolymer,

wherein the dip-formed article has an elongation of more than 650% and satisfies the following Expressions 1 and 2,

[Math. 17]

[Expression 1]

k 1 ′+k 2 ′+k 3 ′≤9.3 N/mm  (1)

[Expression 2]

0.55≤ k 1 ′/( k 1 ′+k 2 ′+k 3 ′)  (2)

wherein k 1 ′ is a value obtained by dividing an equilibrium coefficient k 1 by a thickness of a test piece, and k 2 ′ and k 3 ′ are values obtained by dividing viscous coefficients k 2 and k 3 by the thickness of the test piece, respectively, and

wherein the carboxylic acid-modified nitrile-based copolymer latex satisfies the following Expressions 3 and 4,

[Expression 3]

1.0≤CV 0 ≤3.0 mm 2 /s  (3)

[Expression 4]

0.8≤ P≤ 1, P =CV D /CV 0   (4)

wherein CV 0 represents a capillary viscosity of the carboxylic acid-modified nitrile-based copolymer latex in a swollen state, and CV D represents a capillary viscosity of the carboxylic acid-modified nitrile-based copolymer latex in a de-swollen state.

2 . The dip-formed article of claim 1 , wherein the latex composition for dip-forming further comprises an epoxy crosslinking agent, an aluminum crosslinking agent, water, and a pH adjuster.

3 . The dip-formed article of claim 2 , wherein

the amount of the aluminum crosslinking agent added is 0.1 to 0.8 parts by weight in terms of aluminum oxide based on 100 parts by weight of the carboxylic acid-modified nitrile-based copolymer, and

when both the epoxy crosslinking agent and the aluminum crosslinking agent are added, a total amount of the epoxy crosslinking agent and aluminum crosslinking agent added is 0.2 to 1.6 parts by weight based on 100 parts by weight of the carboxylic acid-modified nitrile-based copolymer.

4 . The dip-formed article of claim 2 , wherein the amount of the epoxy crosslinking agent added is 0.2 to 1.0 part by weight based on 100 parts by weight of the carboxylic acid-modified nitrile-based copolymer,

the amount of the aluminum crosslinking agent added is 0.2 to 0.7 parts by weight in terms of aluminum oxide based on 100 parts by weight of the carboxylic acid-modified nitrile-based copolymer, and

when both the epoxy crosslinking agent and the aluminum crosslinking agent are added, a total amount of the epoxy crosslinking agent and aluminum crosslinking agent added is 0.4 to 1.4 parts by weight based on 100 parts by weight of the carboxylic acid-modified nitrile-based copolymer.

5 . The dip-formed article of claim 2 , wherein the epoxy crosslinking agent has three or more glycidyl groups in one molecule, an alicyclic, aliphatic, or aromatic base skeleton, an average number of epoxy groups of more than 2.25, and an MIBK/water distribution ratio of 50% or more, and

the aluminum crosslinking agent is aluminum carboxylate.

6 . A latex composition for dip-forming, comprising: at least

the carboxylic acid-modified nitrile-based copolymer latex of claim 1 ;

an epoxy crosslinking agent; and

an aluminum crosslinking agent.