Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2002-11-14
2003-11-18
Sergent, Rabon (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C524S591000, C524S839000, C528S071000, C528S905000, C528S085000
Reexamination Certificate
active
06649693
ABSTRACT:
TECHNICAL FIELD
The present invention relates to aqueous polyurethane resins exhibiting a superior adhesive property, bonding property, weather resistance, water resistance, and the like, and polyurethanes for use in these resins.
BACKGROUND ART
Aqueous polyurethane resins are widely employed as resins for use in coating materials, adhesives, binders, inks, or the like since they exhibit superior dynamically physical properties, abrasion resistance, flexibility, and the like. In particular, there is a recent trend for restricting the discharge of organic solvents to the atmosphere in view of the environmental protection of the earth, and for this reason, in the future, applications of aqueous polyurethane resins may be broadened in various uses.
As aqueous polyurethane resins, those prepared from a diol having an acidic group such as dimethylol propionic acid, dimethylol butanoic acid, or the like as a raw material, and the acidic group of which is neutralized by a base are known (Japanese Examined Patent Application, Second Publication No. Sho 61-5485, Japanese Examined Patent Application, Second Publication No. Hei 4-488, Japanese Unexamined Patent Application, First Publication No. Hei 8-27242, and Japanese Unexamined Patent Application, First Publication No. Hei 6-329744).
For the case where aqueous polyurethane resins are employed for use in coating materials, adhesives, or the like, they are required to exhibit characteristics of maintaining physical properties for a long period of time, such as weather resistance, water resistance, and the like, as well as to exhibit a superior adhesive property and bonding property. However, the aqueous polyurethane resins disclosed in the publications described above cannot practically meet the performance requirements.
In addition, WO96/09334 discloses polyurethanes employing 2,4-diethyl-1,5-pentanediol. The polyurethanes disclosed in the Examples of said publication cannot form an aqueous polyurethane resin due to their low solubility in water or the like.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide an aqueous polyurethane resins exhibiting a superior adhesive property, bonding property, weather resistance, water resistance, and the like, and to provide polyurethanes employed in said resins.
That is, the present invention provides polyurethanes comprising in a molecule: an acidic group which is neutralized by a basic compound; and a structural unit represented by general formula (I):
(in the formula, R
1
and R
2
are identical or different, and represent a lower alkyl group).
In addition, the present invention provides an aqueous polyurethane resins comprising said polyurethane.
In the definition of the groups of general formula (I), examples of the lower alkyl groups include straight or branched alkyl groups having 1 to 8 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an isoamyl group, a neopentyl group, a 2-pentyl group, a 3-pentyl group, a hexyl group, a heptyl group, an octyl group, and the like.
In addition, examples of the acidic groups include a carboxyl group, a sulfo group, a phosphono group, and the like. Among these, a carboxyl group is preferable.
Examples of the basic compounds for neutralizing the acidic group include the basic compounds described below.
The polyurethanes of the present invention can be synthesized according to known methods (Japanese Unexamined Patent Application, First Publication No. Hei 8-27242, Japanese Unexamined Patent Application, First Publication No. Hei 8-259884, or the like).
One example of the methods for preparing a polyurethane of the present invention is explained in (1) to (3) below.
(1) Preparation of a polyester polyol: 2,4-Dialkyl-1,5-pentanediol which is a diol comprising a structural unit in a molecule, the unit represented by general formula (I), is reacted with a dicarboxylic acid to produce a polyester polyol.
(2) Preparation of a urethane prepolymer and neutralization of the same: The above polyester polyol, a compound having an acidic group, and a polyisocyanate are reacted to produce a urethane prepolymer having an isocyanate group at the terminal. Then, the acidic group of the above urethane prepolymer is neutralized by a basic compound.
(3) Preparation of a polyurethane: The above urethane prepolymer, wherein the acidic group is neutralized, is reacted with a chain-elongation agent to produce a polyurethane according to the present invention.
In the following, steps (1) to (3) are explained in more detail.
(1) Preparation of the Polyester Polyol:
A polyester polyol can be obtained from 2,4-dialkyl-1,5-pentanediol and a dicarboxylic acid according to a known method (such as that described in Japanese Unexamined Patent Application, First Publication No. Sho 48-101496, WO98/44014, WO99/06498, or the like) by, for example, heating them, or heating them under reduced pressure, followed by dehydration polycondensation.
Examples of the dicarboxylic acids include succinic acid, adipic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, phthalic acid, and the like. They can be employed alone or in combination with two or more of the same. In addition, instead of the dicarboxylic acid, an acid anhydride of the dicarboxylic acid or a lower alkyl ester of the dicarboxylic acid, such as a methyl ester, an ethyl ester, or the like, may be employed.
2,4-Dialkyl-1,5-pentanediol can be prepared according to a method described in WO97/19904, or alternatively is commercially available.
Furthermore, in addition to 2,4-dialkyl-1,5-pentanediol, other diols may be simultaneously employed. In this case, the ratio of 2,4-dialkyl-1,5-pentanediol to the total of the diols is preferably 30% by weight or more, and more preferably is 40% by weight or more.
Examples of the other diols which can be simultaneously employed include ethylene glycol, propylene glycol, 1,4-butanediol, diethylene glycol, 1,6-hexanediol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 1,4-bis(&bgr;-hydroxyethoxy)benzene, and the like. In the case of employing these other diols, a random polycondensation may be carried out.
The molar ratio of the diol with respect to the dicarboxylic acid in the raw materials is not particularly restricted. It preferably ranges from 1.0 to 2.0, and more preferably ranges from 1.1 to 1.5.
The temperature during production of the polyester polyol is not particularly restricted. It preferably ranges from 100 to 300° C., and more preferably ranges from 150 to 250° C.
The number average molecular weight of the polyester polyol preferably ranges from 400 to 8,000, and more preferably ranges from 600 to 5,000.
In addition, it is preferable that the polyester polyol be produced without employing solvents. However, solvents which are inert with respect to the reaction may be employed, and for example, ketones such as methyl ethyl ketone, methyl isobutyl ketone, or the like, ethers such as tetrahydrofuran or the like, aromatic hydrocarbons such as benzene, toluene, xylene, or the like may be employed.
(2) Preparation of the Urethane Prepolymer and Neutralization of the Same:
As a raw material for a urethane prepolymer, a mixture produced by mixing, in a polyester polyol which is a raw material for the urethane prepolymer, other kinds of polyols such as a polycarbonate polyol, a polyether polyol, or the like may be employed. In this case, the ratio of the polyester polyol employed to the total of the polyols is preferably from 50% by weight or more, and more preferably is from 70% by weight or more.
Examples of the compounds having an acidic group include compounds which have an acidic group such as a carboxyl group, a sulfonic group, a phosphono group, or the like, and preferably have a carboxyl group, in a molecule, and have two or more groups having an activated hydrogen capable of reacting with an isocyanate group, such as a hydroxyl group or the like in a molecule.
Thus, examples of the compounds having an acidic gro
Konishi Shohei
Murata Shigeru
Yamauchi Toshio
Kyowa Yuka Co., Ltd.
Sergent Rabon
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