Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
2001-06-22
2003-08-19
Sellers, Robert E. L. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C252S182230, C252S183110, C525S411000
Reexamination Certificate
active
06608148
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to reactive hot melt adhesive compositions applied by hot melt coating and cured by application of actinic radiation.
BACKGROUND OF THE INVENTION
In the fields of bookbinding, packing, textile processing, electronics, transportation and so on, hot melt adhesives have been known as adhesives widely utilized for adhesion of paper, fibers, wood, glass, plastics, metal and others.
A hot melt adhesive is, when being actually used, hot melted in an applicator normally at temperature of the order ranging from 100 to 200° C.
The hot melt adhesive coated on an article is cooled and solidified to make the article to adhere.
Such a hot melt adhesive normally has a very short time of one minute or less to reveal a adhesion strength after articles are bonded together. Hence, an adhesion operation can be completed in a short time.
However, a hot melt adhesive is required to be melted by heating; therefore, the adhesive generally has a weak point of poor heat resistance.
Therefore, studies have been widely conducted in order to improve heat resistance through introduction of a curing mechanism based on a chemical reaction into a coating/adhering operation of a hot melt adhesive.
For example, a hot melt adhesive of a moisture-initiating curing type is disclosed in JP-A-74-98445.
Since a curing reaction progresses in this hot melt adhesive by moisture in the air, storage stability is poor and the curing reaction is slow, and a problem is further pointed out and working environments are adversely affected by the presence of the adhesive since the adhesive contains isocyanate based material, which results in insufficient curing when the adhesive is applied to moistureproof materials.
Then, a hot melt composition, excellent in heat resistance, and composed of an epoxy compound and a polyester compound together with a photo-initiator is disclosed as a reactive hot melt composition of a non-moisture-initiating curing type in JPA-94-306346.
On the other hand, replacement of vinyl chloride resin has been rapidly advanced from the viewpoint of an environmental problem in recent years.
For example, studies have been conducted on replacement of an PVC film with a polyester film (PET) on a great scale.
However, since PET is generally an article of poor adhesiveness, the hot melt composition disclosed in JP-A-94-306346 has had a problem since no sufficient adhesion strength is obtained when PET is used as an article to which the hot melt composition is applied.
In light of the above described problems, it is an object of the present invention to provide a reactive hot melt adhesive, in which a curing reaction progresses under application of actinic radiation, and excellent in not only heat resistance but also adhesiveness to PET.
DISCLOSURE OF THE INVENTION
1. The first aspect of the invention is a reactive hot melt adhesive composition comprising: a cationically polymerizable compound, on the average per molecule, having one or more cationically polymerizable reactive groups of a structure of the following formula (1); a phthalate diester compound of a structure of the following formula (2); and a cationic photo-initiator:
where in the formula (1), R
1
, R
2
, R
3
and R
4
each indicate a hydrogen atom, a methyl group, an ethyl group, an isopropyl group, an isoamyl group or a phenyl group, provided that m and n each are an integer having a value of 0, 1 or 2, and
wherein in the formula (2O), R
5
indicates (C
h
H
2h
)
i
H and R
6
indicates (C
k
H
2k
O)
1
H or (C
k
H
2k
O)
1
C
k
H
2k+1
, provided that h, i, k and l each are an integer having a value of 1 or more
2. The second aspect of the invention is a reactive hot melt adhesive composition comprising: a cationically polymerizable compound, on the average per molecule, having one or more cationically polymerizable reactive groups of a structure of the following formula (1); a phthalate diester compound of a structure of the following formula (3); and a cationic photo-initiator:
where in the formula (1), R
1
, R
2
, R
3
and R
4
each indicate a hydrogen atom, a methyl group, an ethyl group, an isopropyl group, an isoamyl group or a phenyl group, provided that m and n each are an integer having a value of 0, 1 or 2,
wherein in the formula (3), R
7
indicates a cationically polymerizable group of a structure of the following formula (4), R
8
indicates a cationically polymerizable group of a structure of the following formula (4), H or an alkyl group, provided that h and k each are an integer having a value of 1 or more and i and 1 each are an integer having a value of 0 and 1 or more, and
wherein in the formula (4), R
1
, R
2
, R
3
and R
4
each indicate a hydrogen atom, a methyl group, an ethyl group, an isopropyl group, an isoamyl group, or a phenyl group and R
9
indicates an alkyl group or a hydrogen atom, provided that j is an integer having a value of 0 and 1 or more and m and n each are an integer having a value of 0, 1 or 2.
The first and second aspects of the invention can further comprise a thermoplastic resin. Furthermore, the cationically polymerizable reactive group of the cationically polymerizable compound can be an epoxy group.
THE BEST MODES OF THE EMBODIMENTS
A cationically polymerizable compound used in the present invention (the invention according to claim
1
) is not limited specifically but may be any of compounds as long as each of them is a compound, on the average/per molecule, having one or more cationically polymerizable reactive groups of a structure of the above described formula (1).
The cationically polymerizable compound may be a monomer, an oligomer, or a polymer, and may includes a constituent atom such as a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom, a sulfur atom and a phosphorous atom. The cationically polymerizable reactive group may be either a terminal group or a side-branched group of a molecule, or may reside in the molecule and further, has no limitation on a structure and a molecular weight.
A cationically polymerizable compound itself may be a hot melt resin. Besides, the cationically polymerizable compound may be a liquid at a normal temperature, in which case, a liquid cationically polymerizable compound and a solid thermoplastic resin are blended and provided as a solid composition.
As such cationically polymerizable compounds, preferably named are, for example, cyclic ether compounds such as an epoxy compound, an oxetane compound and an oxolane compound.
Among them, the epoxy compound is preferably used because of its excellent cationically polymerizing properties.
Furthermore, among epoxy compounds, a bisphenol based epoxy resin is preferred because of a high degree of improvement on adhesiveness and to be concrete, there can be named a bisphenol A type, bisphenol⇄F type, a bisphenol⇄S type and a bisphenol⇄AD type.
Among them, a bispenol⇄F epoxy resin is especially preferably used because of excellency in adhesiveness to PET.
Cationically polymerizable compounds may be used in combinations comprising two or more kinds.
Thermoplastic resins used in the present invention may be any of resins as long as they are melted by heating and solidified by cooling, which are:
for example, polyolefins resin such as polyethylene and polypropylene; elastomer resins such as polybutadiene, polychloroprene, polyisoprene, styrene-butadiene copolymer and acrylonitrile-butadiene copolymer; polyether resins such as polyethylene oxide, polypropylene oxide and polytetramethylene oxide; polyvinyl based resins such as polyvinyl acetate, ethylene-vinyl acetate copolymer, polyvinyl chloride, ethylene-vinyl chloride copolymer, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyvinyl formal, polyvinyl butyral, and polyvinyl ether; (meta)acryl copolymer resin, styrol resin, polyester resin, polycarbonate resin, ketone resin, acrylonitril-stylene copolymer resin and acrylonitril-butadiene-stylene copolymer resin.
Among the above described resins, resins assuming a solid state at 20° C. are prefera
Hasegawa Tsuyoshi
Kuroda Takeo
Matsuda Masanori
Miyake Takeshi
Shinjo Takashi
Sekisui Chemical Company, Ltd.
Sellers Robert E. L.
Townsend & Banta
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