Adhesive composition and optical member using the same
An adhesive composition and an optical member using the same, the adhesive composition including an acrylic resin; an isocyanate cross-linking agent; and a carbodiimide cross-linking agent, wherein the adhesive composition exhibits a creeping distance of about 100 μm or less when the composition attached to a glass substrate with a bonding area of about 1.5 cm×1.5 cm is left at about 22° C. and about 50% RH for about 3 days and is subjected to a load of about 10 gf/mm 2 for about 1,000 seconds, and a storage modulus of about 1×10 5 to about 1×10 7 Pa at about 10 Hz and about 30° C. under conditions in which a sample has a thickness of about 1 mm and an elongation of about 10%.
1. An adhesive composition, comprising:
an acrylic resin;
an isocyanate cross-linking agent; and
a carbodiimide cross-linking agent, wherein:
the adhesive composition has a creeping distance of about 100 μm or less when the composition attached to a glass substrate with a bonding area of about 1.5 cm×1.5 cm is left at about 22° C. and about 50% RH for about 3 days and is subjected to a load of about 10 gf/mm 2 for about 1,000 seconds,
the adhesive composition has a storage modulus of about 1×10 5 to about 1×10 7 Pa at about 10 Hz and about 30 ° C. under conditions in which a sample has a thickness of about 1 mm and an elongation of about 10%, and
a difference between 180° peel strength (P1) and 180° Peel strength (P4) of the adhesive composition is 100 g/25 mm or less, where 180° peel strength (P1) is a 180° peel strength of a specimen measured by JIS 2107 between the adhesive composition and the glass substrate after the specimen was left for 1 day, and 180° peel strength (P4) is a 180° peel strength of the specimen measured by JIS 2107 between the adhesive composition and the glass substrate after the specimen was left for 4 days wherein the adhesive composition includes:
100 parts by weight of the acrylic resin;
about 1 to about 30 parts by weight of the isocyanate cross-linking agent;
about 0.001 to about 1 part by weight of the carbodiimide cross-linking agent; and wherein a weight ratio of the isocyanate cross-linking agent to the carbodiimide cross-linking agent is about 500:1 to about 3,000:1.
2. The adhesive composition as claimed in claim 1 , wherein the acrylic resin includes a (meth)acrylate copolymer, the (meth)acrylate copolymer including about 0.01 to about 5 wt % of repeating units of a hydroxyl group containing monomer.
3. The adhesive composition as claimed in claim 1 , wherein the acrylic resin includes:
a first (meth)acrylate copolymer including less than about 0.01 wt % of repeating units of a hydroxyl group containing monomer, and
a second (meth)acrylate copolymer including about 0.01 to about 5 wt % of repeating units of a hydroxyl group containing monomer.
4. The adhesive composition as claimed in claim 3 , wherein the acrylic resin includes:
about 85 to about 99 wt % of the first (meth)acrylate copolymer, and
about 1 to about 15 wt % of the second (meth)acrylate copolymer.
5. The adhesive composition as claimed in claim 3 , wherein:
the first (meth)acrylate copolymer has a weight average molecular weight of about 1,000,000 to about 2,000,000 g/mol, and
the second (meth)acrylate copolymer has a weight average molecular weight of about 500,000 to about 1,500,000 g/mol.
6. The adhesive composition as claimed in claim 3 , wherein:
the first (meth)acrylate copolymer is polymerized from a monomer mixture including:
about 85 to about 99.99 wt % of C1 to C20 alkyl (meth)acrylate,
less than about 0.01 wt % of a hydroxyl group containing monomer, and
about 0.01 to about 15 wt % of a carboxyl group containing monomer, and
the second (meth)acrylate copolymer is polymerized from a monomer mixture including:
about 90 to about 99 wt % of C1 to C20 alkyl (meth)acrylate,
about 0.01 to about 5 wt % of a hydroxyl group containing monomer, and
about 0.1 to about 5 wt % of a carboxyl group containing monomer.
7. The adhesive composition as claimed in claim 1 , wherein the acrylic resin has a weight average molecular weight of about 1,500,000 to about 3,000,000 g/mol.
8. The adhesive composition as claimed in claim 1 further comprising about 0.01 to 20 parts by weight of a silane coupling agent.
9. The adhesive composition as claimed in claim 1 , wherein the adhesive composition includes:
100 parts by weight of the acrylic resin;
greater than about 10 parts by weight to less than about 30 parts by weight of the isocyanate cross-linking agent; and
about 0.005 to about 0.1 parts by weight of the carbodiimide cross-linking agent.
10. An optical member, comprising:
an optical film; and
an adhesive layer prepared from the adhesive composition as claimed in claim 1 , the adhesive layer being on one or more sides of the optical film.
11. The optical member as claimed in claim 10 , wherein the optical member has a 180° peel strength of about 250 to 600 gf/25mm between an adhesive and a glass substrate at a tensile rate of about 300 mm/min by JIS 2107 when the optical member is left at about 35° C. and about 45% RH for about 1 day and then stabilized at about 25° C. for about 12 hours.
12. An adhesive composition, comprising:
100 parts by weight of an acrylic resin, the acrylic resin including a (meth)acrylate copolymer including about 0.01 to about 5 wt % of repeating units of a hydroxyl group containing monomer;
about 1 to about 30 parts by weight of an isocyanate cross-linking agent; and
a carbodiimide cross-linking agent in an amount such that a weight ratio of the isocyanate cross-linking agent to the carbodiimide cross-linking agent is about 500:1 to about 3,000:1,
wherein a difference between 180° peel strength (P1) and 180° peel strength (P4) is 100 g/25mm or less (where, 180° peel strength (P1) is a 180° peel strength of a specimen measured by JIS 2107 between the adhesive composition and the glass substrate after the specimen was left for 1 day, 180° peel strength (P4) is a 180° peel strength of the specimen measured by JIS 2107 between the adhesive composition and the glass substrate after the specimen was left for 4 days).