Two-component curable solventless adhesive
A two-component curable solventless adhesive which enables a laminated composite film comprising a barrier layer and a plastic film laminated with each other to maintain excellent appearance and adhesive strength for a long period even after a sterilization treatment at high temperature, and to appropriately adjust a reaction between a base resin and a curing agent during a production of the laminated composite film. The two-component curable solventless adhesive comprises a base resin and a curing agent, wherein the base resin contains a polyol having an acid group and a secondary or tertiary terminal hydroxyl group accounting for 30% or more of the entire terminal hydroxyl groups of the polyol, and the curing agent contains an isocyanate group-terminated urethane prepolymer containing at least an aralkyl polyisocyanate and/or a modified substance thereof as a raw polyisocyanate, and a content of a low molecular weight polyisocyanate is defined.
1. A two-component curable solventless adhesive consisting of a base resin and a curing agent, wherein
the base resin contains a polyol having an acid group, a secondary or tertiary terminal hydroxyl group accounts for 30% or more of the entire terminal hydroxyl groups of the polyol, and 0.3 mol % or more and below 20 mol % of the entire terminal hydroxyl groups of the polyol is modified with a trimellitic anhydride, and
the curing agent contains an isocyanate group-terminated urethane prepolymer obtained by reaction of a raw polyisocyanate containing at least an aralkyl polyisocyanate and/or a modified substance thereof with a macropolyol having a number average molecular weight of 400 to 5000, and a content of a low molecular weight polyisocyanate having a molecular weight of 190 or less is 3% by weight or less, and
a value calculated from the following formula (1) is 10 or more and 30 or less:
(
Acid
equivalent
of
base
resin
)
×
(
Amount
of
curing
agent
(
parts
by
weight
)
)
(
Isocyanate
equivalent
of
curing
agent
)
×
(
Amount
of
base
resin
(
parts
by
weight
)
)
.
(
1
)
2. The two-component curable solventless adhesive according to claim 1 , wherein an average functionality of the isocyanate group-terminated urethane prepolymer is from 1.5 to 2.5.
3. The two-component curable solventless adhesive according to claim 1 , wherein the curing agent contains an aliphatic polyisocyanate and/or a modified substance thereof, and
a content of the isocyanate group-terminated urethane prepolymer is from 1 to 80% by weight and a content of the aliphatic polyisocyanate and/or the modified substance thereof is from 20 to 99% by weight, based on a total amount of the isocyanate group-terminated urethane prepolymer and the aliphatic polyisocyanate and/or the modified substance thereof in the curing agent.
4. The two-component curable solventless adhesive according to claim 1 used to laminate a barrier layer and a plastic film.
5. A two-component curable solventless adhesive comprising a base resin and a curing agent, wherein
the base resin contains a polyol having an acid group, and a secondary or tertiary terminal hydroxyl group accounts for 30% or more of the entire terminal hydroxyl groups of a molecular of the polyol, and 0.3 mol % or more and below 20 mol % of the entire terminal hydroxyl groups of the molecular of the polyol is modified with a trimellitic anhydride, and
the curing agent contains an isocyanate group-terminated urethane prepolymer obtained by reaction of a raw polyisocyanate containing at least an aralkyl polyisocyanate and/or a modified substance thereof with a macropolyol having a number average molecular weight of 400 to 5000, and a value calculated from the following formula (1) is 10 or more and 30 or less:
(
Acid
equivalent
of
base
resin
)
×
(
Amount
of
curing
agent
(
parts
by
weight
)
)
(
Isocyanate
equivalent
of
curing
agent
)
×
(
Amount
of
base
resin
(
parts
by
weight
)
)
.
(
1
)